DJ
Didier Juges
Mon, May 28, 2007 11:53 AM
Ulrich,
I am quite familiar with the cannon analogy. If I may use this analogy
too, please consider the following:
There must be a force balancing the force of gravity, otherwise the
satellite would not cease from accelerating under gravity alone.
Gravity exerts a force on the satellite which tends to make it fall
towards earth. This is the Centripetal force. Inertia due to the mass of
the satellite makes it resist this motion, and the tangential speed
makes it miss the earth. Centrifugal force is the name we give to that
resistance. When the satellite is in a stable orbit, it does not
accelerate because both forces exactly balance each other. For the
reason you pointed out, in a closed system the sum of forces must be
zero, so there must be a force balancing the gravity force. So I see we
agree.
If there was no rotation, that force would not exist and the satellite
would accelerate (under gravity alone) towards earth.
Dont be confused by terminology. The terms centrifugal and centripetal
are just names given to other forces, not actual forces by themselves.
The centripetal force is due to gravity (but is could be
electromagnetic, or anything else. In a centrifuge, it would be the
force exerted by the rotating arm), the centrifugal force is due to
mass, radius and speed.
73,
Didier KO4BB
-----Original Message-----
From: Ulrich Bangert [mailto:df6jb@ulrich-bangert.de]
Sent: Monday, May 28, 2007 5:03 AM
To: 'Didier Juges'
Subject: AW: [time-nuts] Pendulums & Atomic Clocks & Gravity
Didier,
I am an physicist, not an engineer.
Let me use an experiment of thought that Bill Hawkins has already used
in the discussion: Assume an cannon mounted in an certain height with
the barrel mounted tangetial to earth's surface. Fire an bullet and see
it fall to earth after an certain time of flight. Now use more gun
powder and see the the bullet fall to earth later. Use a BIG amount of
powder and see the bullet leave earth's gravity completely. Between the
extremes: Drop to surface and leaving earth's gravity completely there
is one powder loading that brings the bullet into an circular orbit at
the height of the cannon. The bullet never stops to "fall" to earth.
However the motion towards earth's cencer is compensated by the fact
that an tangential motion ALSO means to depart from the center of the
body that you move tangential to.
73 and my best regards
Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: Didier Juges [mailto:didier@cox.net]
Gesendet: Montag, 28. Mai 2007 02:02
An: df6jb@ulrich-bangert.de
Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity
Ulrich,
Please go ahead, I am all ears... (in all seriousness, I am not a
physicist, just an engineer)
If earth attracts the satellite and the satellite attracts earth, how
come the satellite and earth don't get together?
What is keeping them apart?
When you say the gravity forces are of opposite direction, this is
correct. The gravity applied by earth to the satellite causes a force
vector directed towards the earth, the gravity applied by the satellite
to earth is a force vector of equal magnitude and directed from earth to
the satellite. The external result is null (as a system, there is no
"loss" of force, action = reaction).
The same holds true for centrifugal forces. The satellite affects the
orbit of earth in proportion of their respective mass, so the satellite
causes earth to move around it's theoretical orbit (if there was no
satellite). The earth movement is very small (could not be measured for
an artificial satellite, but but could certainly be calculated, the
effect of the moon on earth's orbit can certainly be measured) but it
causes an equal and opposite centrifugal force on earth, which balances
the force exerted on the satellite.
So I believe there are 2 sets of forces (gravity and centrifugal), and
each set has a resultant that is null, as seen from the outside.
However, at the level of earth and the satellite, the gravitational
attraction is equal and opposite to the centrifugal force.
I did not know physics cared if we used inertial system concepts or
accelerated systems concepts (I do not know the difference).
If I follow your theory, the speed of the satellite around the earth has
no effect on gravity, so the satellite should stay where it is
regardless of speed, but it does not!
Please explain this to me.
I agree that as long as the distance between a satellite and earth
remains constant, the forces must balance each other. But if it's not
centrifugal force that is balancing gravity, what is it?
Thanks in advance
Didier
Ulrich Bangert wrote:
Didier,
gravitational forces, so do objects in Lagrange points. These points
represent areas where the centrifugal forces compensate for
gravity....
I am almost sure that this will again produce me a lot of trouble in
answering a lot of people but the idea that there are centrifugal forces
which compensate for gravity are one of the BIGGEST misconcepts that one
may have in physics at all although it is quite common and you may find
statements like that eben in (bad) physics textbooks.
Centrifugal forces are so called fictitious forces which are only
observed from within accelerated systems. Normal physics is done in
inertial systems. In an inertial system consisting of earth and an
satellite there are only TWO forces available: The gravity force by
which earth attracts the satellite and the gravitational force by which
the satellite attracts earth. They are of the same magnitude but of
opposite direction. That is the reason why the "sum of forces" is zero
for the closed system consisting of earth and satellite. There is no
place for any other force like centrifugal or so because there is no
counterforce available that would make the sum of forces zero i case a
centrifugal force would exist. In case you like to discuss it a bit
please go on but be prepared that I will to blow your arguments into
little bits. A good idea to start with is to look after what Newton's
first law is saying about the behaviour of a body for which all forces
compensate each other. Is that what a satellite does???
73 Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
Gesendet: Sonntag, 27. Mai 2007 16:54
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity
For the same reason that a satellite in free fall is still subject to
gravitational forces, so do objects in Lagrange points. These points
represent areas where the centrifugal forces compensate for
gravity from
two objects instead of one for a regular satellite. The only
way to be
free from gravitation is infinite distance from mass, until someone
actually invents the famous gravitational shield :-) I hope
it comes in
spray form...
Didier
Neville Michie wrote:
Look up Lagrangian points on Wikipedia.
There are points of zero gravitational force, about our planet. What
is more, these points are stationary with respect to Earth, so
Doppler effects would be zero.
As the distance from Sun to Earth to Moon varies through
the year it
follows that the distance from Earth of these points must
vary on a
small scale.
These points are good for satelites as the orbit never decays.
cheers, Neville Michie
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Ulrich,
I am quite familiar with the cannon analogy. If I may use this analogy
too, please consider the following:
There must be a force balancing the force of gravity, otherwise the
satellite would not cease from accelerating under gravity alone.
Gravity exerts a force on the satellite which tends to make it fall
towards earth. This is the Centripetal force. Inertia due to the mass of
the satellite makes it resist this motion, and the tangential speed
makes it miss the earth. Centrifugal force is the name we give to that
resistance. When the satellite is in a stable orbit, it does not
accelerate because both forces exactly balance each other. For the
reason you pointed out, in a closed system the sum of forces must be
zero, so there must be a force balancing the gravity force. So I see we
agree.
If there was no rotation, that force would not exist and the satellite
would accelerate (under gravity alone) towards earth.
Dont be confused by terminology. The terms centrifugal and centripetal
are just names given to other forces, not actual forces by themselves.
The centripetal force is due to gravity (but is could be
electromagnetic, or anything else. In a centrifuge, it would be the
force exerted by the rotating arm), the centrifugal force is due to
mass, radius and speed.
73,
Didier KO4BB
-----Original Message-----
From: Ulrich Bangert [mailto:df6jb@ulrich-bangert.de]
Sent: Monday, May 28, 2007 5:03 AM
To: 'Didier Juges'
Subject: AW: [time-nuts] Pendulums & Atomic Clocks & Gravity
Didier,
I am an physicist, not an engineer.
Let me use an experiment of thought that Bill Hawkins has already used
in the discussion: Assume an cannon mounted in an certain height with
the barrel mounted tangetial to earth's surface. Fire an bullet and see
it fall to earth after an certain time of flight. Now use more gun
powder and see the the bullet fall to earth later. Use a BIG amount of
powder and see the bullet leave earth's gravity completely. Between the
extremes: Drop to surface and leaving earth's gravity completely there
is one powder loading that brings the bullet into an circular orbit at
the height of the cannon. The bullet never stops to "fall" to earth.
However the motion towards earth's cencer is compensated by the fact
that an tangential motion ALSO means to depart from the center of the
body that you move tangential to.
73 and my best regards
Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: Didier Juges [mailto:didier@cox.net]
Gesendet: Montag, 28. Mai 2007 02:02
An: df6jb@ulrich-bangert.de
Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity
Ulrich,
Please go ahead, I am all ears... (in all seriousness, I am not a
physicist, just an engineer)
If earth attracts the satellite and the satellite attracts earth, how
come the satellite and earth don't get together?
What is keeping them apart?
When you say the gravity forces are of opposite direction, this is
correct. The gravity applied by earth to the satellite causes a force
vector directed towards the earth, the gravity applied by the satellite
to earth is a force vector of equal magnitude and directed from earth to
the satellite. The external result is null (as a system, there is no
"loss" of force, action = reaction).
The same holds true for centrifugal forces. The satellite affects the
orbit of earth in proportion of their respective mass, so the satellite
causes earth to move around it's theoretical orbit (if there was no
satellite). The earth movement is very small (could not be measured for
an artificial satellite, but but could certainly be calculated, the
effect of the moon on earth's orbit can certainly be measured) but it
causes an equal and opposite centrifugal force on earth, which balances
the force exerted on the satellite.
So I believe there are 2 sets of forces (gravity and centrifugal), and
each set has a resultant that is null, as seen from the outside.
However, at the level of earth and the satellite, the gravitational
attraction is equal and opposite to the centrifugal force.
I did not know physics cared if we used inertial system concepts or
accelerated systems concepts (I do not know the difference).
If I follow your theory, the speed of the satellite around the earth has
no effect on gravity, so the satellite should stay where it is
regardless of speed, but it does not!
Please explain this to me.
I agree that as long as the distance between a satellite and earth
remains constant, the forces must balance each other. But if it's not
centrifugal force that is balancing gravity, what is it?
Thanks in advance
Didier
Ulrich Bangert wrote:
Didier,
gravitational forces, so do objects in Lagrange points. These points
represent areas where the centrifugal forces compensate for
gravity....
I am almost sure that this will again produce me a lot of trouble in
answering a lot of people but the idea that there are centrifugal forces
which compensate for gravity are one of the BIGGEST misconcepts that one
may have in physics at all although it is quite common and you may find
statements like that eben in (bad) physics textbooks.
Centrifugal forces are so called fictitious forces which are only
observed from within accelerated systems. Normal physics is done in
inertial systems. In an inertial system consisting of earth and an
satellite there are only TWO forces available: The gravity force by
which earth attracts the satellite and the gravitational force by which
the satellite attracts earth. They are of the same magnitude but of
opposite direction. That is the reason why the "sum of forces" is zero
for the closed system consisting of earth and satellite. There is no
place for any other force like centrifugal or so because there is no
counterforce available that would make the sum of forces zero i case a
centrifugal force would exist. In case you like to discuss it a bit
please go on but be prepared that I will to blow your arguments into
little bits. A good idea to start with is to look after what Newton's
first law is saying about the behaviour of a body for which all forces
compensate each other. Is that what a satellite does???
73 Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
Gesendet: Sonntag, 27. Mai 2007 16:54
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity
For the same reason that a satellite in free fall is still subject to
gravitational forces, so do objects in Lagrange points. These points
represent areas where the centrifugal forces compensate for
gravity from
two objects instead of one for a regular satellite. The only
way to be
free from gravitation is infinite distance from mass, until someone
actually invents the famous gravitational shield :-) I hope
it comes in
spray form...
Didier
Neville Michie wrote:
Look up Lagrangian points on Wikipedia.
There are points of zero gravitational force, about our planet. What
is more, these points are stationary with respect to Earth, so
Doppler effects would be zero.
As the distance from Sun to Earth to Moon varies through
the year it
follows that the distance from Earth of these points must
vary on a
small scale.
These points are good for satelites as the orbit never decays.
cheers, Neville Michie
_______________________________________________
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
_______________________________________________
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
_______________________________________________
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
_______________________________________________
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
UB
Ulrich Bangert
Mon, May 28, 2007 12:24 PM
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
Gesendet: Montag, 28. Mai 2007 13:53
An: time-nuts@febo.com
Betreff: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Ulrich,
I am quite familiar with the cannon analogy. If I may use
this analogy too, please consider the following:
There must be a force balancing the force of gravity,
otherwise the satellite would not cease from accelerating
under gravity alone.
Gravity exerts a force on the satellite which tends to make
it fall towards earth. This is the Centripetal force. Inertia
due to the mass of the satellite makes it resist this motion,
and the tangential speed makes it miss the earth.
Centrifugal force is the name we give to that resistance.
When the satellite is in a stable orbit, it does not
accelerate because both forces exactly balance each other.
For the reason you pointed out, in a closed system the sum of
forces must be zero, so there must be a force balancing the
gravity force. So I see we agree.
If there was no rotation, that force would not exist and the
satellite would accelerate (under gravity alone) towards earth.
Dont be confused by terminology. The terms centrifugal and
centripetal are just names given to other forces, not actual
forces by themselves. The centripetal force is due to gravity
(but is could be electromagnetic, or anything else. In a
centrifuge, it would be the force exerted by the rotating
arm), the centrifugal force is due to mass, radius and speed.
73,
Didier KO4BB
-----Original Message-----
From: Ulrich Bangert [mailto:df6jb@ulrich-bangert.de]
Sent: Monday, May 28, 2007 5:03 AM
To: 'Didier Juges'
Subject: AW: [time-nuts] Pendulums & Atomic Clocks & Gravity
Didier,
I am an physicist, not an engineer.
Let me use an experiment of thought that Bill Hawkins has
already used in the discussion: Assume an cannon mounted in
an certain height with the barrel mounted tangetial to
earth's surface. Fire an bullet and see it fall to earth
after an certain time of flight. Now use more gun powder and
see the the bullet fall to earth later. Use a BIG amount of
powder and see the bullet leave earth's gravity completely.
Between the
extremes: Drop to surface and leaving earth's gravity
completely there is one powder loading that brings the bullet
into an circular orbit at the height of the cannon. The
bullet never stops to "fall" to earth. However the motion
towards earth's cencer is compensated by the fact that an
tangential motion ALSO means to depart from the center of the
body that you move tangential to.
73 and my best regards
Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: Didier Juges [mailto:didier@cox.net]
Gesendet: Montag, 28. Mai 2007 02:02
An: df6jb@ulrich-bangert.de
Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity Ulrich,
Please go ahead, I am all ears... (in all seriousness, I am
not a physicist, just an engineer)
If earth attracts the satellite and the satellite attracts
earth, how come the satellite and earth don't get together?
What is keeping them apart?
When you say the gravity forces are of opposite direction,
this is correct. The gravity applied by earth to the
satellite causes a force vector directed towards the earth,
the gravity applied by the satellite to earth is a force
vector of equal magnitude and directed from earth to the
satellite. The external result is null (as a system, there is
no "loss" of force, action = reaction).
The same holds true for centrifugal forces. The satellite
affects the orbit of earth in proportion of their respective
mass, so the satellite causes earth to move around it's
theoretical orbit (if there was no satellite). The earth
movement is very small (could not be measured for an
artificial satellite, but but could certainly be calculated,
the effect of the moon on earth's orbit can certainly be
measured) but it causes an equal and opposite centrifugal
force on earth, which balances the force exerted on the satellite.
So I believe there are 2 sets of forces (gravity and
centrifugal), and each set has a resultant that is null, as
seen from the outside. However, at the level of earth and the
satellite, the gravitational attraction is equal and opposite
to the centrifugal force.
I did not know physics cared if we used inertial system
concepts or accelerated systems concepts (I do not know the
difference).
If I follow your theory, the speed of the satellite around
the earth has no effect on gravity, so the satellite should
stay where it is regardless of speed, but it does not!
Please explain this to me.
I agree that as long as the distance between a satellite and
earth remains constant, the forces must balance each other.
But if it's not centrifugal force that is balancing gravity,
what is it?
Thanks in advance
Didier
Ulrich Bangert wrote:
Didier,
gravitational forces, so do objects in Lagrange points. These points
represent areas where the centrifugal forces compensate for
gravity....
I am almost sure that this will again produce me a lot of
trouble in answering a lot of people but the idea that there
are centrifugal forces which compensate for gravity are one
of the BIGGEST misconcepts that one may have in physics at
all although it is quite common and you may find statements
like that eben in (bad) physics textbooks.
Centrifugal forces are so called fictitious forces which are
only observed from within accelerated systems. Normal physics
is done in inertial systems. In an inertial system consisting
of earth and an satellite there are only TWO forces
available: The gravity force by which earth attracts the
satellite and the gravitational force by which the satellite
attracts earth. They are of the same magnitude but of
opposite direction. That is the reason why the "sum of
forces" is zero for the closed system consisting of earth and
satellite. There is no place for any other force like
centrifugal or so because there is no counterforce available
that would make the sum of forces zero i case a centrifugal
force would exist. In case you like to discuss it a bit
please go on but be prepared that I will to blow your
arguments into little bits. A good idea to start with is to
look after what Newton's first law is saying about the
behaviour of a body for which all forces compensate each
other. Is that what a satellite does???
73 Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
Gesendet: Sonntag, 27. Mai 2007 16:54
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity
For the same reason that a satellite in free fall is still subject to
gravitational forces, so do objects in Lagrange points. These points
represent areas where the centrifugal forces compensate for
gravity from
two objects instead of one for a regular satellite. The only
way to be
free from gravitation is infinite distance from mass, until someone
actually invents the famous gravitational shield :-) I hope
it comes in
spray form...
Didier
Neville Michie wrote:
Look up Lagrangian points on Wikipedia.
There are points of zero gravitational force, about our
planet. What is more, these points are stationary with
respect to Earth, so
Doppler effects would be zero.
As the distance from Sun to Earth to Moon varies through
the year it
follows that the distance from Earth of these points must
vary on a
small scale.
These points are good for satelites as the orbit never
decays. cheers, Neville Michie
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> -----Ursprüngliche Nachricht-----
> Von: time-nuts-bounces@febo.com
> [mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
> Gesendet: Montag, 28. Mai 2007 13:53
> An: time-nuts@febo.com
> Betreff: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
>
>
> Ulrich,
>
> I am quite familiar with the cannon analogy. If I may use
> this analogy too, please consider the following:
>
> There must be a force balancing the force of gravity,
> otherwise the satellite would not cease from accelerating
> under gravity alone.
>
> Gravity exerts a force on the satellite which tends to make
> it fall towards earth. This is the Centripetal force. Inertia
> due to the mass of the satellite makes it resist this motion,
> and the tangential speed makes it miss the earth.
> Centrifugal force is the name we give to that resistance.
> When the satellite is in a stable orbit, it does not
> accelerate because both forces exactly balance each other.
> For the reason you pointed out, in a closed system the sum of
> forces must be zero, so there must be a force balancing the
> gravity force. So I see we agree.
>
> If there was no rotation, that force would not exist and the
> satellite would accelerate (under gravity alone) towards earth.
>
> Dont be confused by terminology. The terms centrifugal and
> centripetal are just names given to other forces, not actual
> forces by themselves. The centripetal force is due to gravity
> (but is could be electromagnetic, or anything else. In a
> centrifuge, it would be the force exerted by the rotating
> arm), the centrifugal force is due to mass, radius and speed.
>
> 73,
> Didier KO4BB
>
> -----Original Message-----
> From: Ulrich Bangert [mailto:df6jb@ulrich-bangert.de]
> Sent: Monday, May 28, 2007 5:03 AM
> To: 'Didier Juges'
> Subject: AW: [time-nuts] Pendulums & Atomic Clocks & Gravity
>
> Didier,
>
> I am an physicist, not an engineer.
>
> Let me use an experiment of thought that Bill Hawkins has
> already used in the discussion: Assume an cannon mounted in
> an certain height with the barrel mounted tangetial to
> earth's surface. Fire an bullet and see it fall to earth
> after an certain time of flight. Now use more gun powder and
> see the the bullet fall to earth later. Use a BIG amount of
> powder and see the bullet leave earth's gravity completely.
> Between the
> extremes: Drop to surface and leaving earth's gravity
> completely there is one powder loading that brings the bullet
> into an circular orbit at the height of the cannon. The
> bullet never stops to "fall" to earth. However the motion
> towards earth's cencer is compensated by the fact that an
> tangential motion ALSO means to depart from the center of the
> body that you move tangential to.
>
> 73 and my best regards
> Ulrich, DF6JB
> -----Ursprüngliche Nachricht-----
> Von: Didier Juges [mailto:didier@cox.net]
> Gesendet: Montag, 28. Mai 2007 02:02
> An: df6jb@ulrich-bangert.de
> Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity Ulrich,
>
> Please go ahead, I am all ears... (in all seriousness, I am
> not a physicist, just an engineer)
>
> If earth attracts the satellite and the satellite attracts
> earth, how come the satellite and earth don't get together?
> What is keeping them apart?
>
> When you say the gravity forces are of opposite direction,
> this is correct. The gravity applied by earth to the
> satellite causes a force vector directed towards the earth,
> the gravity applied by the satellite to earth is a force
> vector of equal magnitude and directed from earth to the
> satellite. The external result is null (as a system, there is
> no "loss" of force, action = reaction).
>
> The same holds true for centrifugal forces. The satellite
> affects the orbit of earth in proportion of their respective
> mass, so the satellite causes earth to move around it's
> theoretical orbit (if there was no satellite). The earth
> movement is very small (could not be measured for an
> artificial satellite, but but could certainly be calculated,
> the effect of the moon on earth's orbit can certainly be
> measured) but it causes an equal and opposite centrifugal
> force on earth, which balances the force exerted on the satellite.
>
> So I believe there are 2 sets of forces (gravity and
> centrifugal), and each set has a resultant that is null, as
> seen from the outside. However, at the level of earth and the
> satellite, the gravitational attraction is equal and opposite
> to the centrifugal force.
>
> I did not know physics cared if we used inertial system
> concepts or accelerated systems concepts (I do not know the
> difference).
>
> If I follow your theory, the speed of the satellite around
> the earth has no effect on gravity, so the satellite should
> stay where it is regardless of speed, but it does not!
>
> Please explain this to me.
>
> I agree that as long as the distance between a satellite and
> earth remains constant, the forces must balance each other.
> But if it's not centrifugal force that is balancing gravity,
> what is it?
>
> Thanks in advance
>
> Didier
>
> Ulrich Bangert wrote:
> Didier,
>
>
> gravitational forces, so do objects in Lagrange points. These points
> represent areas where the centrifugal forces compensate for
> gravity....
>
>
> I am almost sure that this will again produce me a lot of
> trouble in answering a lot of people but the idea that there
> are centrifugal forces which compensate for gravity are one
> of the BIGGEST misconcepts that one may have in physics at
> all although it is quite common and you may find statements
> like that eben in (bad) physics textbooks.
>
> Centrifugal forces are so called fictitious forces which are
> only observed from within accelerated systems. Normal physics
> is done in inertial systems. In an inertial system consisting
> of earth and an satellite there are only TWO forces
> available: The gravity force by which earth attracts the
> satellite and the gravitational force by which the satellite
> attracts earth. They are of the same magnitude but of
> opposite direction. That is the reason why the "sum of
> forces" is zero for the closed system consisting of earth and
> satellite. There is no place for any other force like
> centrifugal or so because there is no counterforce available
> that would make the sum of forces zero i case a centrifugal
> force would exist. In case you like to discuss it a bit
> please go on but be prepared that I will to blow your
> arguments into little bits. A good idea to start with is to
> look after what Newton's first law is saying about the
> behaviour of a body for which all forces compensate each
> other. Is that what a satellite does???
>
> 73 Ulrich, DF6JB
>
>
> -----Ursprüngliche Nachricht-----
> Von: time-nuts-bounces@febo.com
> [mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
> Gesendet: Sonntag, 27. Mai 2007 16:54
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity
>
>
> For the same reason that a satellite in free fall is still subject to
> gravitational forces, so do objects in Lagrange points. These points
> represent areas where the centrifugal forces compensate for
> gravity from
> two objects instead of one for a regular satellite. The only
> way to be
> free from gravitation is infinite distance from mass, until someone
> actually invents the famous gravitational shield :-) I hope
> it comes in
> spray form...
>
> Didier
>
> Neville Michie wrote:
>
> Look up Lagrangian points on Wikipedia.
> There are points of zero gravitational force, about our
> planet. What is more, these points are stationary with
> respect to Earth, so
> Doppler effects would be zero.
> As the distance from Sun to Earth to Moon varies through
>
> the year it
>
> follows that the distance from Earth of these points must
>
> vary on a
>
> small scale.
> These points are good for satelites as the orbit never
> decays. cheers, Neville Michie
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
>
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
>
>
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
>
UB
Ulrich Bangert
Mon, May 28, 2007 1:22 PM
Didier,
let us consider the more easier case of an linear motion. Imagine an
body that can glide on an surface without any friction. Now you take a
finger of your hand and press it on one side of the body so that it
moves horizontally. Clearly your finger exercises an force on the body
that makes it accelerate. And in your finger you feel an force into the
opposite direction.
The key question is about the physical reality of this force in the
opposite direction.
How big is it? I guess, you would argument that it has the same
magnitude as the force that you apply with your finger but has the
opposite direction, right? Now you have TWO forces. If they have the
same magnitude but opposite direction their vectors add to zero and I am
almost sure you would argument that this makes the sum of forces zero
for the system.
Now, that you have shown that the sum of forces is zero you are in the
ungraceful position in that you must explain why the body IS
ACCELERATING at all. According to F=m*a a non-zero F is necessary to
generate a non-zero a. How do you explain?
Please note that in physics there is one substantial thing that one must
know about forces and counterforces: They never affect on the SAME body
but always on DIFFERENT bodies. In case you do not believe take the next
textbook and read it after. For the above experiment this means: Since
BOTH forces that you are talking about affect on the same one body one
of the forces CANNOT be the counterforce to the other. If this is so
then lets search for the counterforce for the force that you apply with
your finger. In order to be able to execute this force your feet or
other parts of your body execute an force into opposite direction to the
surface of earth. These two forces are counterforces to each other
because they
a) have opposite directions
b) have same magnitude
c) apply to different bodies.
Now that we have found the counterforce that makes the sum of forces
zero for the system you need to find the counterforce to your inertial
force and you will find none. Perhaps it is helpful for your
understanding that one of the definitions for fictitious forces is that
no counterforce belonging to them can be found. And if no counterforce
can be found they have NO physical reality because otherwise the rule of
the sum of forces is violated.
There was only ONE force F acting on the body that make it accelerate
according F=m*a and this force had its source in your finger. To be able
to execute this force you "pressed against earth" into the opposite
direction and that makes the sum of forces zero. This is the only
correct physical explanation of this example. ALL forces due to effects
of inertia are fictitious forces.
73 and my best regards
Ulrich, DF6JB
P.S.
Newton's first law says that a body at which all forces compensate keeps
it current state of motion. To keep the current state of motion a body
a) has to keep its velocity
and
b) has to keep its direction of flight.
It this what a satellite does? No, it permanently changes its direction
of flight due to earth's gravitational force. If there were compensating
forces the satellite would move away along a straight line.
Please note: I knew before that this would make a big discussion because
the misconception is spread that wide. Perhaps you even learned this at
school. When I worked as an "Wissenschaftlicher Mitarbeiter" (comparable
to an assistent professor) at the department of physics of the German
university at Bochum such miconceptions were one of our favourite
subsects of study in teaching physics.
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
Gesendet: Montag, 28. Mai 2007 13:53
An: time-nuts@febo.com
Betreff: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Ulrich,
I am quite familiar with the cannon analogy. If I may use
this analogy too, please consider the following:
There must be a force balancing the force of gravity,
otherwise the satellite would not cease from accelerating
under gravity alone.
Gravity exerts a force on the satellite which tends to make
it fall towards earth. This is the Centripetal force. Inertia
due to the mass of the satellite makes it resist this motion,
and the tangential speed makes it miss the earth.
Centrifugal force is the name we give to that resistance.
When the satellite is in a stable orbit, it does not
accelerate because both forces exactly balance each other.
For the reason you pointed out, in a closed system the sum of
forces must be zero, so there must be a force balancing the
gravity force. So I see we agree.
If there was no rotation, that force would not exist and the
satellite would accelerate (under gravity alone) towards earth.
Dont be confused by terminology. The terms centrifugal and
centripetal are just names given to other forces, not actual
forces by themselves. The centripetal force is due to gravity
(but is could be electromagnetic, or anything else. In a
centrifuge, it would be the force exerted by the rotating
arm), the centrifugal force is due to mass, radius and speed.
73,
Didier KO4BB
-----Original Message-----
From: Ulrich Bangert [mailto:df6jb@ulrich-bangert.de]
Sent: Monday, May 28, 2007 5:03 AM
To: 'Didier Juges'
Subject: AW: [time-nuts] Pendulums & Atomic Clocks & Gravity
Didier,
I am an physicist, not an engineer.
Let me use an experiment of thought that Bill Hawkins has
already used in the discussion: Assume an cannon mounted in
an certain height with the barrel mounted tangetial to
earth's surface. Fire an bullet and see it fall to earth
after an certain time of flight. Now use more gun powder and
see the the bullet fall to earth later. Use a BIG amount of
powder and see the bullet leave earth's gravity completely.
Between the
extremes: Drop to surface and leaving earth's gravity
completely there is one powder loading that brings the bullet
into an circular orbit at the height of the cannon. The
bullet never stops to "fall" to earth. However the motion
towards earth's cencer is compensated by the fact that an
tangential motion ALSO means to depart from the center of the
body that you move tangential to.
73 and my best regards
Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: Didier Juges [mailto:didier@cox.net]
Gesendet: Montag, 28. Mai 2007 02:02
An: df6jb@ulrich-bangert.de
Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity Ulrich,
Please go ahead, I am all ears... (in all seriousness, I am
not a physicist, just an engineer)
If earth attracts the satellite and the satellite attracts
earth, how come the satellite and earth don't get together?
What is keeping them apart?
When you say the gravity forces are of opposite direction,
this is correct. The gravity applied by earth to the
satellite causes a force vector directed towards the earth,
the gravity applied by the satellite to earth is a force
vector of equal magnitude and directed from earth to the
satellite. The external result is null (as a system, there is
no "loss" of force, action = reaction).
The same holds true for centrifugal forces. The satellite
affects the orbit of earth in proportion of their respective
mass, so the satellite causes earth to move around it's
theoretical orbit (if there was no satellite). The earth
movement is very small (could not be measured for an
artificial satellite, but but could certainly be calculated,
the effect of the moon on earth's orbit can certainly be
measured) but it causes an equal and opposite centrifugal
force on earth, which balances the force exerted on the satellite.
So I believe there are 2 sets of forces (gravity and
centrifugal), and each set has a resultant that is null, as
seen from the outside. However, at the level of earth and the
satellite, the gravitational attraction is equal and opposite
to the centrifugal force.
I did not know physics cared if we used inertial system
concepts or accelerated systems concepts (I do not know the
difference).
If I follow your theory, the speed of the satellite around
the earth has no effect on gravity, so the satellite should
stay where it is regardless of speed, but it does not!
Please explain this to me.
I agree that as long as the distance between a satellite and
earth remains constant, the forces must balance each other.
But if it's not centrifugal force that is balancing gravity,
what is it?
Thanks in advance
Didier
Ulrich Bangert wrote:
Didier,
gravitational forces, so do objects in Lagrange points. These points
represent areas where the centrifugal forces compensate for
gravity....
I am almost sure that this will again produce me a lot of
trouble in answering a lot of people but the idea that there
are centrifugal forces which compensate for gravity are one
of the BIGGEST misconcepts that one may have in physics at
all although it is quite common and you may find statements
like that eben in (bad) physics textbooks.
Centrifugal forces are so called fictitious forces which are
only observed from within accelerated systems. Normal physics
is done in inertial systems. In an inertial system consisting
of earth and an satellite there are only TWO forces
available: The gravity force by which earth attracts the
satellite and the gravitational force by which the satellite
attracts earth. They are of the same magnitude but of
opposite direction. That is the reason why the "sum of
forces" is zero for the closed system consisting of earth and
satellite. There is no place for any other force like
centrifugal or so because there is no counterforce available
that would make the sum of forces zero i case a centrifugal
force would exist. In case you like to discuss it a bit
please go on but be prepared that I will to blow your
arguments into little bits. A good idea to start with is to
look after what Newton's first law is saying about the
behaviour of a body for which all forces compensate each
other. Is that what a satellite does???
73 Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
Gesendet: Sonntag, 27. Mai 2007 16:54
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity
For the same reason that a satellite in free fall is still subject to
gravitational forces, so do objects in Lagrange points. These points
represent areas where the centrifugal forces compensate for
gravity from
two objects instead of one for a regular satellite. The only
way to be
free from gravitation is infinite distance from mass, until someone
actually invents the famous gravitational shield :-) I hope
it comes in
spray form...
Didier
Neville Michie wrote:
Look up Lagrangian points on Wikipedia.
There are points of zero gravitational force, about our
planet. What is more, these points are stationary with
respect to Earth, so
Doppler effects would be zero.
As the distance from Sun to Earth to Moon varies through
the year it
follows that the distance from Earth of these points must
vary on a
small scale.
These points are good for satelites as the orbit never
decays. cheers, Neville Michie
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
Didier,
let us consider the more easier case of an linear motion. Imagine an
body that can glide on an surface without any friction. Now you take a
finger of your hand and press it on one side of the body so that it
moves horizontally. Clearly your finger exercises an force on the body
that makes it accelerate. And in your finger you feel an force into the
opposite direction.
The key question is about the physical reality of this force in the
opposite direction.
How big is it? I guess, you would argument that it has the same
magnitude as the force that you apply with your finger but has the
opposite direction, right? Now you have TWO forces. If they have the
same magnitude but opposite direction their vectors add to zero and I am
almost sure you would argument that this makes the sum of forces zero
for the system.
Now, that you have shown that the sum of forces is zero you are in the
ungraceful position in that you must explain why the body IS
ACCELERATING at all. According to F=m*a a non-zero F is necessary to
generate a non-zero a. How do you explain?
Please note that in physics there is one substantial thing that one must
know about forces and counterforces: They never affect on the SAME body
but always on DIFFERENT bodies. In case you do not believe take the next
textbook and read it after. For the above experiment this means: Since
BOTH forces that you are talking about affect on the same one body one
of the forces CANNOT be the counterforce to the other. If this is so
then lets search for the counterforce for the force that you apply with
your finger. In order to be able to execute this force your feet or
other parts of your body execute an force into opposite direction to the
surface of earth. These two forces are counterforces to each other
because they
a) have opposite directions
b) have same magnitude
c) apply to different bodies.
Now that we have found the counterforce that makes the sum of forces
zero for the system you need to find the counterforce to your inertial
force and you will find none. Perhaps it is helpful for your
understanding that one of the definitions for fictitious forces is that
no counterforce belonging to them can be found. And if no counterforce
can be found they have NO physical reality because otherwise the rule of
the sum of forces is violated.
There was only ONE force F acting on the body that make it accelerate
according F=m*a and this force had its source in your finger. To be able
to execute this force you "pressed against earth" into the opposite
direction and that makes the sum of forces zero. This is the only
correct physical explanation of this example. ALL forces due to effects
of inertia are fictitious forces.
73 and my best regards
Ulrich, DF6JB
P.S.
Newton's first law says that a body at which all forces compensate keeps
it current state of motion. To keep the current state of motion a body
a) has to keep its velocity
and
b) has to keep its direction of flight.
It this what a satellite does? No, it permanently changes its direction
of flight due to earth's gravitational force. If there were compensating
forces the satellite would move away along a straight line.
Please note: I knew before that this would make a big discussion because
the misconception is spread that wide. Perhaps you even learned this at
school. When I worked as an "Wissenschaftlicher Mitarbeiter" (comparable
to an assistent professor) at the department of physics of the German
university at Bochum such miconceptions were one of our favourite
subsects of study in teaching physics.
> -----Ursprüngliche Nachricht-----
> Von: time-nuts-bounces@febo.com
> [mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
> Gesendet: Montag, 28. Mai 2007 13:53
> An: time-nuts@febo.com
> Betreff: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
>
>
> Ulrich,
>
> I am quite familiar with the cannon analogy. If I may use
> this analogy too, please consider the following:
>
> There must be a force balancing the force of gravity,
> otherwise the satellite would not cease from accelerating
> under gravity alone.
>
> Gravity exerts a force on the satellite which tends to make
> it fall towards earth. This is the Centripetal force. Inertia
> due to the mass of the satellite makes it resist this motion,
> and the tangential speed makes it miss the earth.
> Centrifugal force is the name we give to that resistance.
> When the satellite is in a stable orbit, it does not
> accelerate because both forces exactly balance each other.
> For the reason you pointed out, in a closed system the sum of
> forces must be zero, so there must be a force balancing the
> gravity force. So I see we agree.
>
> If there was no rotation, that force would not exist and the
> satellite would accelerate (under gravity alone) towards earth.
>
> Dont be confused by terminology. The terms centrifugal and
> centripetal are just names given to other forces, not actual
> forces by themselves. The centripetal force is due to gravity
> (but is could be electromagnetic, or anything else. In a
> centrifuge, it would be the force exerted by the rotating
> arm), the centrifugal force is due to mass, radius and speed.
>
> 73,
> Didier KO4BB
>
> -----Original Message-----
> From: Ulrich Bangert [mailto:df6jb@ulrich-bangert.de]
> Sent: Monday, May 28, 2007 5:03 AM
> To: 'Didier Juges'
> Subject: AW: [time-nuts] Pendulums & Atomic Clocks & Gravity
>
> Didier,
>
> I am an physicist, not an engineer.
>
> Let me use an experiment of thought that Bill Hawkins has
> already used in the discussion: Assume an cannon mounted in
> an certain height with the barrel mounted tangetial to
> earth's surface. Fire an bullet and see it fall to earth
> after an certain time of flight. Now use more gun powder and
> see the the bullet fall to earth later. Use a BIG amount of
> powder and see the bullet leave earth's gravity completely.
> Between the
> extremes: Drop to surface and leaving earth's gravity
> completely there is one powder loading that brings the bullet
> into an circular orbit at the height of the cannon. The
> bullet never stops to "fall" to earth. However the motion
> towards earth's cencer is compensated by the fact that an
> tangential motion ALSO means to depart from the center of the
> body that you move tangential to.
>
> 73 and my best regards
> Ulrich, DF6JB
> -----Ursprüngliche Nachricht-----
> Von: Didier Juges [mailto:didier@cox.net]
> Gesendet: Montag, 28. Mai 2007 02:02
> An: df6jb@ulrich-bangert.de
> Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity Ulrich,
>
> Please go ahead, I am all ears... (in all seriousness, I am
> not a physicist, just an engineer)
>
> If earth attracts the satellite and the satellite attracts
> earth, how come the satellite and earth don't get together?
> What is keeping them apart?
>
> When you say the gravity forces are of opposite direction,
> this is correct. The gravity applied by earth to the
> satellite causes a force vector directed towards the earth,
> the gravity applied by the satellite to earth is a force
> vector of equal magnitude and directed from earth to the
> satellite. The external result is null (as a system, there is
> no "loss" of force, action = reaction).
>
> The same holds true for centrifugal forces. The satellite
> affects the orbit of earth in proportion of their respective
> mass, so the satellite causes earth to move around it's
> theoretical orbit (if there was no satellite). The earth
> movement is very small (could not be measured for an
> artificial satellite, but but could certainly be calculated,
> the effect of the moon on earth's orbit can certainly be
> measured) but it causes an equal and opposite centrifugal
> force on earth, which balances the force exerted on the satellite.
>
> So I believe there are 2 sets of forces (gravity and
> centrifugal), and each set has a resultant that is null, as
> seen from the outside. However, at the level of earth and the
> satellite, the gravitational attraction is equal and opposite
> to the centrifugal force.
>
> I did not know physics cared if we used inertial system
> concepts or accelerated systems concepts (I do not know the
> difference).
>
> If I follow your theory, the speed of the satellite around
> the earth has no effect on gravity, so the satellite should
> stay where it is regardless of speed, but it does not!
>
> Please explain this to me.
>
> I agree that as long as the distance between a satellite and
> earth remains constant, the forces must balance each other.
> But if it's not centrifugal force that is balancing gravity,
> what is it?
>
> Thanks in advance
>
> Didier
>
> Ulrich Bangert wrote:
> Didier,
>
>
> gravitational forces, so do objects in Lagrange points. These points
> represent areas where the centrifugal forces compensate for
> gravity....
>
>
> I am almost sure that this will again produce me a lot of
> trouble in answering a lot of people but the idea that there
> are centrifugal forces which compensate for gravity are one
> of the BIGGEST misconcepts that one may have in physics at
> all although it is quite common and you may find statements
> like that eben in (bad) physics textbooks.
>
> Centrifugal forces are so called fictitious forces which are
> only observed from within accelerated systems. Normal physics
> is done in inertial systems. In an inertial system consisting
> of earth and an satellite there are only TWO forces
> available: The gravity force by which earth attracts the
> satellite and the gravitational force by which the satellite
> attracts earth. They are of the same magnitude but of
> opposite direction. That is the reason why the "sum of
> forces" is zero for the closed system consisting of earth and
> satellite. There is no place for any other force like
> centrifugal or so because there is no counterforce available
> that would make the sum of forces zero i case a centrifugal
> force would exist. In case you like to discuss it a bit
> please go on but be prepared that I will to blow your
> arguments into little bits. A good idea to start with is to
> look after what Newton's first law is saying about the
> behaviour of a body for which all forces compensate each
> other. Is that what a satellite does???
>
> 73 Ulrich, DF6JB
>
>
> -----Ursprüngliche Nachricht-----
> Von: time-nuts-bounces@febo.com
> [mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
> Gesendet: Sonntag, 27. Mai 2007 16:54
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity
>
>
> For the same reason that a satellite in free fall is still subject to
> gravitational forces, so do objects in Lagrange points. These points
> represent areas where the centrifugal forces compensate for
> gravity from
> two objects instead of one for a regular satellite. The only
> way to be
> free from gravitation is infinite distance from mass, until someone
> actually invents the famous gravitational shield :-) I hope
> it comes in
> spray form...
>
> Didier
>
> Neville Michie wrote:
>
> Look up Lagrangian points on Wikipedia.
> There are points of zero gravitational force, about our
> planet. What is more, these points are stationary with
> respect to Earth, so
> Doppler effects would be zero.
> As the distance from Sun to Earth to Moon varies through
>
> the year it
>
> follows that the distance from Earth of these points must
>
> vary on a
>
> small scale.
> These points are good for satelites as the orbit never
> decays. cheers, Neville Michie
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
>
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
>
>
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
>
DJ
Didier Juges
Mon, May 28, 2007 3:59 PM
Ulrich,
Your comparison with the linear motion is not valid. While you push the
body, it accelerates. The energy spent giving the body increased speed
(due to the excess force applied to the body while there is no counter
force) is stored in kinetic energy. Once you stop pushing, the body
moves straight at constant speed and there is no more force either way,
the state of motion does not change.
Going back to the satellite, I believe we agree in principal but you are
hung up on the first law definition. The corollary to the first law is
that objects resist change to their state of motion. They resist that
change via inertia. Inertia causes real forces to be developed. I agree
it's not a fundamental force like gravity or electromagnetism, but it is
necessary to keep the system in equilibrium, otherwise what would be
holding the satellite at a constant distance while it is being pulled
towards earth?
Example: a car is moving at 1m/s. You stand still on the driveway (your
speed: 0m/s.) The car hits you. Because the car is much heavier (err:
has more mass) than you, you now move at close to 1m/s and the car has
just slowed down a bit (m * v stays the same). The car has exerted a
force on you that gave you acceleration. You have exerted a force on the
car that caused the car to change it's speed, you imparted on the car a
certain acceleration in the opposite direction. The only way the car
could feel acceleration is because a force was exerted upon it. The
force that was exerted on the car came from the inertia of your body. It
is a real force. Now, imagine the driveway was itself on a sliding plane
moving at 1m/s in the opposite direction to the car. In fact, the car
was not moving but you were. It makes no difference, once you realize
the only difference is where the reference it. Two forces were
developed. Which one you call action and which one is reaction is
irrelevant. It's only a matter of reference. Because you change the
reference does not make the force go away.
We agree on what is happening, we don't agree on what to call it.
Since you know a lot more about this than I do, I will accept your
statement that centrifugal forces (or more generally inertial forces)
are fictitious, but only because you insist. As long as I can predict
their effect and calculate their magnitude, that's all this engineer is
interested in :-)
73,
Didier KO4BB
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Ulrich Bangert
Sent: Monday, May 28, 2007 8:23 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Didier,
let us consider the more easier case of an linear motion. Imagine an
body that can glide on an surface without any friction. Now you take a
finger of your hand and press it on one side of the body so that it
moves horizontally. Clearly your finger exercises an force on the body
that makes it accelerate. And in your finger you feel an force into the
opposite direction.
The key question is about the physical reality of this force in the
opposite direction.
How big is it? I guess, you would argument that it has the same
magnitude as the force that you apply with your finger but has the
opposite direction, right? Now you have TWO forces. If they have the
same magnitude but opposite direction their vectors add to zero and I am
almost sure you would argument that this makes the sum of forces zero
for the system.
Now, that you have shown that the sum of forces is zero you are in the
ungraceful position in that you must explain why the body IS
ACCELERATING at all. According to F=m*a a non-zero F is necessary to
generate a non-zero a. How do you explain?
Please note that in physics there is one substantial thing that one must
know about forces and counterforces: They never affect on the SAME body
but always on DIFFERENT bodies. In case you do not believe take the next
textbook and read it after. For the above experiment this means: Since
BOTH forces that you are talking about affect on the same one body one
of the forces CANNOT be the counterforce to the other. If this is so
then lets search for the counterforce for the force that you apply with
your finger. In order to be able to execute this force your feet or
other parts of your body execute an force into opposite direction to the
surface of earth. These two forces are counterforces to each other
because they
a) have opposite directions
b) have same magnitude
c) apply to different bodies.
Now that we have found the counterforce that makes the sum of forces
zero for the system you need to find the counterforce to your inertial
force and you will find none. Perhaps it is helpful for your
understanding that one of the definitions for fictitious forces is that
no counterforce belonging to them can be found. And if no counterforce
can be found they have NO physical reality because otherwise the rule of
the sum of forces is violated.
There was only ONE force F acting on the body that make it accelerate
according F=m*a and this force had its source in your finger. To be able
to execute this force you "pressed against earth" into the opposite
direction and that makes the sum of forces zero. This is the only
correct physical explanation of this example. ALL forces due to effects
of inertia are fictitious forces.
73 and my best regards
Ulrich, DF6JB
P.S.
Newton's first law says that a body at which all forces compensate keeps
it current state of motion. To keep the current state of motion a body
a) has to keep its velocity
and
b) has to keep its direction of flight.
It this what a satellite does? No, it permanently changes its direction
of flight due to earth's gravitational force. If there were compensating
forces the satellite would move away along a straight line.
Please note: I knew before that this would make a big discussion because
the misconception is spread that wide. Perhaps you even learned this at
school. When I worked as an "Wissenschaftlicher Mitarbeiter" (comparable
to an assistent professor) at the department of physics of the German
university at Bochum such miconceptions were one of our favourite
subsects of study in teaching physics.
Ulrich,
Your comparison with the linear motion is not valid. While you push the
body, it accelerates. The energy spent giving the body increased speed
(due to the excess force applied to the body while there is no counter
force) is stored in kinetic energy. Once you stop pushing, the body
moves straight at constant speed and there is no more force either way,
the state of motion does not change.
Going back to the satellite, I believe we agree in principal but you are
hung up on the first law definition. The corollary to the first law is
that objects resist change to their state of motion. They resist that
change via inertia. Inertia causes real forces to be developed. I agree
it's not a fundamental force like gravity or electromagnetism, but it is
necessary to keep the system in equilibrium, otherwise what would be
holding the satellite at a constant distance while it is being pulled
towards earth?
Example: a car is moving at 1m/s. You stand still on the driveway (your
speed: 0m/s.) The car hits you. Because the car is much heavier (err:
has more mass) than you, you now move at close to 1m/s and the car has
just slowed down a bit (m * v stays the same). The car has exerted a
force on you that gave you acceleration. You have exerted a force on the
car that caused the car to change it's speed, you imparted on the car a
certain acceleration in the opposite direction. The only way the car
could feel acceleration is because a force was exerted upon it. The
force that was exerted on the car came from the inertia of your body. It
is a real force. Now, imagine the driveway was itself on a sliding plane
moving at 1m/s in the opposite direction to the car. In fact, the car
was not moving but you were. It makes no difference, once you realize
the only difference is where the reference it. Two forces were
developed. Which one you call action and which one is reaction is
irrelevant. It's only a matter of reference. Because you change the
reference does not make the force go away.
We agree on what is happening, we don't agree on what to call it.
Since you know a lot more about this than I do, I will accept your
statement that centrifugal forces (or more generally inertial forces)
are fictitious, but only because you insist. As long as I can predict
their effect and calculate their magnitude, that's all this engineer is
interested in :-)
73,
Didier KO4BB
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Ulrich Bangert
Sent: Monday, May 28, 2007 8:23 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Didier,
let us consider the more easier case of an linear motion. Imagine an
body that can glide on an surface without any friction. Now you take a
finger of your hand and press it on one side of the body so that it
moves horizontally. Clearly your finger exercises an force on the body
that makes it accelerate. And in your finger you feel an force into the
opposite direction.
The key question is about the physical reality of this force in the
opposite direction.
How big is it? I guess, you would argument that it has the same
magnitude as the force that you apply with your finger but has the
opposite direction, right? Now you have TWO forces. If they have the
same magnitude but opposite direction their vectors add to zero and I am
almost sure you would argument that this makes the sum of forces zero
for the system.
Now, that you have shown that the sum of forces is zero you are in the
ungraceful position in that you must explain why the body IS
ACCELERATING at all. According to F=m*a a non-zero F is necessary to
generate a non-zero a. How do you explain?
Please note that in physics there is one substantial thing that one must
know about forces and counterforces: They never affect on the SAME body
but always on DIFFERENT bodies. In case you do not believe take the next
textbook and read it after. For the above experiment this means: Since
BOTH forces that you are talking about affect on the same one body one
of the forces CANNOT be the counterforce to the other. If this is so
then lets search for the counterforce for the force that you apply with
your finger. In order to be able to execute this force your feet or
other parts of your body execute an force into opposite direction to the
surface of earth. These two forces are counterforces to each other
because they
a) have opposite directions
b) have same magnitude
c) apply to different bodies.
Now that we have found the counterforce that makes the sum of forces
zero for the system you need to find the counterforce to your inertial
force and you will find none. Perhaps it is helpful for your
understanding that one of the definitions for fictitious forces is that
no counterforce belonging to them can be found. And if no counterforce
can be found they have NO physical reality because otherwise the rule of
the sum of forces is violated.
There was only ONE force F acting on the body that make it accelerate
according F=m*a and this force had its source in your finger. To be able
to execute this force you "pressed against earth" into the opposite
direction and that makes the sum of forces zero. This is the only
correct physical explanation of this example. ALL forces due to effects
of inertia are fictitious forces.
73 and my best regards
Ulrich, DF6JB
P.S.
Newton's first law says that a body at which all forces compensate keeps
it current state of motion. To keep the current state of motion a body
a) has to keep its velocity
and
b) has to keep its direction of flight.
It this what a satellite does? No, it permanently changes its direction
of flight due to earth's gravitational force. If there were compensating
forces the satellite would move away along a straight line.
Please note: I knew before that this would make a big discussion because
the misconception is spread that wide. Perhaps you even learned this at
school. When I worked as an "Wissenschaftlicher Mitarbeiter" (comparable
to an assistent professor) at the department of physics of the German
university at Bochum such miconceptions were one of our favourite
subsects of study in teaching physics.
UB
Ulrich Bangert
Mon, May 28, 2007 7:15 PM
Since you know a lot more about this than I do, I will accept
your statement that centrifugal forces (or more generally
inertial forces) are fictitious, but only because you insist.
As long as I can predict their effect and calculate their
magnitude, that's all this engineer is interested in :-)
That would be totally wrong! You are just missing the possibility to
gain some new insights into nature.
Your comparison with the linear motion is not valid.
Please note that my intention was not to immediatly compare linear to
circle motion. The example was merely to show you something about about
forces and counterforces. You did not excactly understand it so let me
try to take a second chance:
Inertia causes real forces to be developed.
If this sentence is true then please answer again the following
question: Is there a real inertial counterforce in the linear example or
not?
73s and my best regards
Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
Gesendet: Montag, 28. Mai 2007 17:59
An: 'Discussion of precise time and frequency measurement'
Betreff: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Ulrich,
Your comparison with the linear motion is not valid. While
you push the body, it accelerates. The energy spent giving
the body increased speed (due to the excess force applied to
the body while there is no counter
force) is stored in kinetic energy. Once you stop pushing,
the body moves straight at constant speed and there is no
more force either way, the state of motion does not change.
Going back to the satellite, I believe we agree in principal
but you are hung up on the first law definition. The
corollary to the first law is that objects resist change to
their state of motion. They resist that change via inertia.
Inertia causes real forces to be developed. I agree it's not
a fundamental force like gravity or electromagnetism, but it
is necessary to keep the system in equilibrium, otherwise
what would be holding the satellite at a constant distance
while it is being pulled towards earth?
Example: a car is moving at 1m/s. You stand still on the
driveway (your
speed: 0m/s.) The car hits you. Because the car is much
heavier (err: has more mass) than you, you now move at close
to 1m/s and the car has just slowed down a bit (m * v stays
the same). The car has exerted a force on you that gave you
acceleration. You have exerted a force on the car that caused
the car to change it's speed, you imparted on the car a
certain acceleration in the opposite direction. The only way
the car could feel acceleration is because a force was
exerted upon it. The force that was exerted on the car came
from the inertia of your body. It is a real force. Now,
imagine the driveway was itself on a sliding plane moving at
1m/s in the opposite direction to the car. In fact, the car
was not moving but you were. It makes no difference, once you
realize the only difference is where the reference it. Two
forces were developed. Which one you call action and which
one is reaction is irrelevant. It's only a matter of
reference. Because you change the reference does not make the
force go away.
We agree on what is happening, we don't agree on what to call it.
Since you know a lot more about this than I do, I will accept
your statement that centrifugal forces (or more generally
inertial forces) are fictitious, but only because you insist.
As long as I can predict their effect and calculate their
magnitude, that's all this engineer is interested in :-)
73,
Didier KO4BB
-----Original Message-----
From: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] On Behalf Of Ulrich Bangert
Sent: Monday, May 28, 2007 8:23 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Didier,
let us consider the more easier case of an linear motion.
Imagine an body that can glide on an surface without any
friction. Now you take a finger of your hand and press it on
one side of the body so that it moves horizontally. Clearly
your finger exercises an force on the body that makes it
accelerate. And in your finger you feel an force into the
opposite direction.
The key question is about the physical reality of this force
in the opposite direction.
How big is it? I guess, you would argument that it has the
same magnitude as the force that you apply with your finger
but has the opposite direction, right? Now you have TWO
forces. If they have the same magnitude but opposite
direction their vectors add to zero and I am almost sure you
would argument that this makes the sum of forces zero for the system.
Now, that you have shown that the sum of forces is zero you
are in the ungraceful position in that you must explain why
the body IS ACCELERATING at all. According to F=m*a a
non-zero F is necessary to generate a non-zero a. How do you explain?
Please note that in physics there is one substantial thing
that one must know about forces and counterforces: They never
affect on the SAME body but always on DIFFERENT bodies. In
case you do not believe take the next textbook and read it
after. For the above experiment this means: Since BOTH forces
that you are talking about affect on the same one body one of
the forces CANNOT be the counterforce to the other. If this
is so then lets search for the counterforce for the force
that you apply with your finger. In order to be able to
execute this force your feet or other parts of your body
execute an force into opposite direction to the surface of
earth. These two forces are counterforces to each other because they
a) have opposite directions
b) have same magnitude
c) apply to different bodies.
Now that we have found the counterforce that makes the sum of
forces zero for the system you need to find the counterforce
to your inertial force and you will find none. Perhaps it is
helpful for your understanding that one of the definitions
for fictitious forces is that no counterforce belonging to
them can be found. And if no counterforce can be found they
have NO physical reality because otherwise the rule of the
sum of forces is violated.
There was only ONE force F acting on the body that make it
accelerate according F=m*a and this force had its source in
your finger. To be able to execute this force you "pressed
against earth" into the opposite direction and that makes the
sum of forces zero. This is the only correct physical
explanation of this example. ALL forces due to effects of
inertia are fictitious forces.
73 and my best regards
Ulrich, DF6JB
P.S.
Newton's first law says that a body at which all forces
compensate keeps it current state of motion. To keep the
current state of motion a body
a) has to keep its velocity
and
b) has to keep its direction of flight.
It this what a satellite does? No, it permanently changes its
direction of flight due to earth's gravitational force. If
there were compensating forces the satellite would move away
along a straight line.
Please note: I knew before that this would make a big
discussion because the misconception is spread that wide.
Perhaps you even learned this at school. When I worked as an
"Wissenschaftlicher Mitarbeiter" (comparable to an assistent
professor) at the department of physics of the German
university at Bochum such miconceptions were one of our
favourite subsects of study in teaching physics.
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
Didier,
> Since you know a lot more about this than I do, I will accept
> your statement that centrifugal forces (or more generally
> inertial forces) are fictitious, but only because you insist.
> As long as I can predict their effect and calculate their
> magnitude, that's all this engineer is interested in :-)
That would be totally wrong! You are just missing the possibility to
gain some new insights into nature.
> Your comparison with the linear motion is not valid.
Please note that my intention was not to immediatly compare linear to
circle motion. The example was merely to show you something about about
forces and counterforces. You did not excactly understand it so let me
try to take a second chance:
> Inertia causes real forces to be developed.
If this sentence is true then please answer again the following
question: Is there a real inertial counterforce in the linear example or
not?
73s and my best regards
Ulrich, DF6JB
> -----Ursprüngliche Nachricht-----
> Von: time-nuts-bounces@febo.com
> [mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
> Gesendet: Montag, 28. Mai 2007 17:59
> An: 'Discussion of precise time and frequency measurement'
> Betreff: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
>
>
> Ulrich,
>
> Your comparison with the linear motion is not valid. While
> you push the body, it accelerates. The energy spent giving
> the body increased speed (due to the excess force applied to
> the body while there is no counter
> force) is stored in kinetic energy. Once you stop pushing,
> the body moves straight at constant speed and there is no
> more force either way, the state of motion does not change.
>
> Going back to the satellite, I believe we agree in principal
> but you are hung up on the first law definition. The
> corollary to the first law is that objects resist change to
> their state of motion. They resist that change via inertia.
> Inertia causes real forces to be developed. I agree it's not
> a fundamental force like gravity or electromagnetism, but it
> is necessary to keep the system in equilibrium, otherwise
> what would be holding the satellite at a constant distance
> while it is being pulled towards earth?
>
> Example: a car is moving at 1m/s. You stand still on the
> driveway (your
> speed: 0m/s.) The car hits you. Because the car is much
> heavier (err: has more mass) than you, you now move at close
> to 1m/s and the car has just slowed down a bit (m * v stays
> the same). The car has exerted a force on you that gave you
> acceleration. You have exerted a force on the car that caused
> the car to change it's speed, you imparted on the car a
> certain acceleration in the opposite direction. The only way
> the car could feel acceleration is because a force was
> exerted upon it. The force that was exerted on the car came
> from the inertia of your body. It is a real force. Now,
> imagine the driveway was itself on a sliding plane moving at
> 1m/s in the opposite direction to the car. In fact, the car
> was not moving but you were. It makes no difference, once you
> realize the only difference is where the reference it. Two
> forces were developed. Which one you call action and which
> one is reaction is irrelevant. It's only a matter of
> reference. Because you change the reference does not make the
> force go away.
>
> We agree on what is happening, we don't agree on what to call it.
>
> Since you know a lot more about this than I do, I will accept
> your statement that centrifugal forces (or more generally
> inertial forces) are fictitious, but only because you insist.
> As long as I can predict their effect and calculate their
> magnitude, that's all this engineer is interested in :-)
>
> 73,
> Didier KO4BB
>
>
> -----Original Message-----
> From: time-nuts-bounces@febo.com
> [mailto:time-nuts-bounces@febo.com] On Behalf Of Ulrich Bangert
> Sent: Monday, May 28, 2007 8:23 AM
> To: 'Discussion of precise time and frequency measurement'
> Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
>
> Didier,
>
> let us consider the more easier case of an linear motion.
> Imagine an body that can glide on an surface without any
> friction. Now you take a finger of your hand and press it on
> one side of the body so that it moves horizontally. Clearly
> your finger exercises an force on the body that makes it
> accelerate. And in your finger you feel an force into the
> opposite direction.
>
> The key question is about the physical reality of this force
> in the opposite direction.
>
> How big is it? I guess, you would argument that it has the
> same magnitude as the force that you apply with your finger
> but has the opposite direction, right? Now you have TWO
> forces. If they have the same magnitude but opposite
> direction their vectors add to zero and I am almost sure you
> would argument that this makes the sum of forces zero for the system.
>
> Now, that you have shown that the sum of forces is zero you
> are in the ungraceful position in that you must explain why
> the body IS ACCELERATING at all. According to F=m*a a
> non-zero F is necessary to generate a non-zero a. How do you explain?
>
> Please note that in physics there is one substantial thing
> that one must know about forces and counterforces: They never
> affect on the SAME body but always on DIFFERENT bodies. In
> case you do not believe take the next textbook and read it
> after. For the above experiment this means: Since BOTH forces
> that you are talking about affect on the same one body one of
> the forces CANNOT be the counterforce to the other. If this
> is so then lets search for the counterforce for the force
> that you apply with your finger. In order to be able to
> execute this force your feet or other parts of your body
> execute an force into opposite direction to the surface of
> earth. These two forces are counterforces to each other because they
>
> a) have opposite directions
>
> b) have same magnitude
>
> c) apply to different bodies.
>
> Now that we have found the counterforce that makes the sum of
> forces zero for the system you need to find the counterforce
> to your inertial force and you will find none. Perhaps it is
> helpful for your understanding that one of the definitions
> for fictitious forces is that no counterforce belonging to
> them can be found. And if no counterforce can be found they
> have NO physical reality because otherwise the rule of the
> sum of forces is violated.
>
> There was only ONE force F acting on the body that make it
> accelerate according F=m*a and this force had its source in
> your finger. To be able to execute this force you "pressed
> against earth" into the opposite direction and that makes the
> sum of forces zero. This is the only correct physical
> explanation of this example. ALL forces due to effects of
> inertia are fictitious forces.
>
> 73 and my best regards
> Ulrich, DF6JB
>
> P.S.
>
> Newton's first law says that a body at which all forces
> compensate keeps it current state of motion. To keep the
> current state of motion a body
>
> a) has to keep its velocity
>
> and
>
> b) has to keep its direction of flight.
>
> It this what a satellite does? No, it permanently changes its
> direction of flight due to earth's gravitational force. If
> there were compensating forces the satellite would move away
> along a straight line.
>
> Please note: I knew before that this would make a big
> discussion because the misconception is spread that wide.
> Perhaps you even learned this at school. When I worked as an
> "Wissenschaftlicher Mitarbeiter" (comparable to an assistent
> professor) at the department of physics of the German
> university at Bochum such miconceptions were one of our
> favourite subsects of study in teaching physics.
>
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
>
BH
Bill Hawkins
Mon, May 28, 2007 8:53 PM
-----Original Message-----
From: Ulrich Bangert
Sent: Monday, May 28, 2007 8:23 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
---%< snip ---
In case you do not believe take the next textbook and read it after.
---%< snip again ---
No disrespect intended, but another interesting book is "Why People
Believe Weird Things" by Michael Shermer, original 1997, revised in
2002, ISBN 0-8050-7089-3, paperback. Using many examples, he shows
how an idea can take root and be stubbornly unyielding, even in
intelligent people.
But this is probably not within the scope of "time-nuts."
Best regards,
Bill Hawkins
-----Original Message-----
From: Ulrich Bangert
Sent: Monday, May 28, 2007 8:23 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
---%< snip ---
In case you do not believe take the next textbook and read it after.
---%< snip again ---
No disrespect intended, but another interesting book is "Why People
Believe Weird Things" by Michael Shermer, original 1997, revised in
2002, ISBN 0-8050-7089-3, paperback. Using many examples, he shows
how an idea can take root and be stubbornly unyielding, even in
intelligent people.
But this is probably not within the scope of "time-nuts."
Best regards,
Bill Hawkins
AT
Arnold Tibus
Mon, May 28, 2007 9:41 PM
Ulrich,
I think I am with you, but
let me see wether my simple understanding is correct:
Assuming a object without sensitivity to gravity flying with a
certain (high) speed across space approaching planet terra.
The path of this object would be obviously straight as a line
(as long we are not thinking in astronomical dimensions) , and even
passing the planet in a very short distance, nothing would deviate
this object from this straight way.
If suddenly, only for a short moment, the bypassing object would get
mass, the gravity of both bodys would play its role and accelerate
this mass into direction of the planet, and vice versa. Due to the
immens big mass difference we forget here the orbit or path change
of the planet. The accelerated object does change the direction
somewhat into the planets center of gravity. The amount depends
on the relation between the impulse with direction and the gravitational
impact at that momentary position. After a bend in the path and a
switch off of the object's gravity, the passing object would
continue the straight flight but in a new direction.
As in reality there is no possibilty for such tricks, the approaching object
will receive continuously these deviating gravity impacts, therefore
beeing continuously accelerated to deviate from the linear path
into a orbitical path, if the gravity force is of the right amount, if not
this body will end with an impact or escape after a longer curvature.
Again back on (a new) straight path out of the gravity from
celestial bodys, there are no more other forces acting on this object.
This free flying object does not need any further force or energy to
contiue its way until other forces will stop the way.
Where this object finally did come from, does not change the facts,
this object could have been launched from the planet terra as well,
accelerated sufficiently to end as satellite or as spacevehicle on the
way out of the solar system.
Thinking this way, I could not find any centrifugal forces, active
was only the gravity between this bodys fighting with impuls of the
object. Would this body not just fall down vertically without own
impuls or impetus?
I think the problem thinking on centrifuges is, that the surroundig
object is getting not only the fixation to avoid to escape but as well
the tangential speed / impuls via the coupling and the continuous
acceleration forcing into a circular path.
The outcome should be the same as above.
Just a short analogon for auquatic fans: Driving a ship straight ahaid
with the rudder straight in the middle, the course will be like a line.
Then switching the jet-rudder in the bow on, the water-jet will deviate to
a circular course with the same effects, we do sense the acceleration....
73
Arnold, DK2WT
On Mon, 28 May 2007 21:15:08 +0200, Ulrich Bangert wrote:
Since you know a lot more about this than I do, I will accept
your statement that centrifugal forces (or more generally
inertial forces) are fictitious, but only because you insist.
As long as I can predict their effect and calculate their
magnitude, that's all this engineer is interested in :-)
That would be totally wrong! You are just missing the possibility to
gain some new insights into nature.
Your comparison with the linear motion is not valid.
Please note that my intention was not to immediatly compare linear to
circle motion. The example was merely to show you something about about
forces and counterforces. You did not excactly understand it so let me
try to take a second chance:
Inertia causes real forces to be developed.
If this sentence is true then please answer again the following
question: Is there a real inertial counterforce in the linear example or
not?
73s and my best regards
Ulrich, DF6JB
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
Gesendet: Montag, 28. Mai 2007 17:59
An: 'Discussion of precise time and frequency measurement'
Betreff: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Ulrich,
Your comparison with the linear motion is not valid. While
you push the body, it accelerates. The energy spent giving
the body increased speed (due to the excess force applied to
the body while there is no counter
force) is stored in kinetic energy. Once you stop pushing,
the body moves straight at constant speed and there is no
more force either way, the state of motion does not change.
Going back to the satellite, I believe we agree in principal
but you are hung up on the first law definition. The
corollary to the first law is that objects resist change to
their state of motion. They resist that change via inertia.
Inertia causes real forces to be developed. I agree it's not
a fundamental force like gravity or electromagnetism, but it
is necessary to keep the system in equilibrium, otherwise
what would be holding the satellite at a constant distance
while it is being pulled towards earth?
Example: a car is moving at 1m/s. You stand still on the
driveway (your
speed: 0m/s.) The car hits you. Because the car is much
heavier (err: has more mass) than you, you now move at close
to 1m/s and the car has just slowed down a bit (m * v stays
the same). The car has exerted a force on you that gave you
acceleration. You have exerted a force on the car that caused
the car to change it's speed, you imparted on the car a
certain acceleration in the opposite direction. The only way
the car could feel acceleration is because a force was
exerted upon it. The force that was exerted on the car came
from the inertia of your body. It is a real force. Now,
imagine the driveway was itself on a sliding plane moving at
1m/s in the opposite direction to the car. In fact, the car
was not moving but you were. It makes no difference, once you
realize the only difference is where the reference it. Two
forces were developed. Which one you call action and which
one is reaction is irrelevant. It's only a matter of
reference. Because you change the reference does not make the
force go away.
We agree on what is happening, we don't agree on what to call it.
Since you know a lot more about this than I do, I will accept
your statement that centrifugal forces (or more generally
inertial forces) are fictitious, but only because you insist.
As long as I can predict their effect and calculate their
magnitude, that's all this engineer is interested in :-)
73,
Didier KO4BB
-----Original Message-----
From: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] On Behalf Of Ulrich Bangert
Sent: Monday, May 28, 2007 8:23 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Didier,
let us consider the more easier case of an linear motion.
Imagine an body that can glide on an surface without any
friction. Now you take a finger of your hand and press it on
one side of the body so that it moves horizontally. Clearly
your finger exercises an force on the body that makes it
accelerate. And in your finger you feel an force into the
opposite direction.
The key question is about the physical reality of this force
in the opposite direction.
How big is it? I guess, you would argument that it has the
same magnitude as the force that you apply with your finger
but has the opposite direction, right? Now you have TWO
forces. If they have the same magnitude but opposite
direction their vectors add to zero and I am almost sure you
would argument that this makes the sum of forces zero for the system.
Now, that you have shown that the sum of forces is zero you
are in the ungraceful position in that you must explain why
the body IS ACCELERATING at all. According to F=m*a a
non-zero F is necessary to generate a non-zero a. How do you explain?
Please note that in physics there is one substantial thing
that one must know about forces and counterforces: They never
affect on the SAME body but always on DIFFERENT bodies. In
case you do not believe take the next textbook and read it
after. For the above experiment this means: Since BOTH forces
that you are talking about affect on the same one body one of
the forces CANNOT be the counterforce to the other. If this
is so then lets search for the counterforce for the force
that you apply with your finger. In order to be able to
execute this force your feet or other parts of your body
execute an force into opposite direction to the surface of
earth. These two forces are counterforces to each other because they
a) have opposite directions
b) have same magnitude
c) apply to different bodies.
Now that we have found the counterforce that makes the sum of
forces zero for the system you need to find the counterforce
to your inertial force and you will find none. Perhaps it is
helpful for your understanding that one of the definitions
for fictitious forces is that no counterforce belonging to
them can be found. And if no counterforce can be found they
have NO physical reality because otherwise the rule of the
sum of forces is violated.
There was only ONE force F acting on the body that make it
accelerate according F=m*a and this force had its source in
your finger. To be able to execute this force you "pressed
against earth" into the opposite direction and that makes the
sum of forces zero. This is the only correct physical
explanation of this example. ALL forces due to effects of
inertia are fictitious forces.
73 and my best regards
Ulrich, DF6JB
P.S.
Newton's first law says that a body at which all forces
compensate keeps it current state of motion. To keep the
current state of motion a body
a) has to keep its velocity
and
b) has to keep its direction of flight.
It this what a satellite does? No, it permanently changes its
direction of flight due to earth's gravitational force. If
there were compensating forces the satellite would move away
along a straight line.
Please note: I knew before that this would make a big
discussion because the misconception is spread that wide.
Perhaps you even learned this at school. When I worked as an
"Wissenschaftlicher Mitarbeiter" (comparable to an assistent
professor) at the department of physics of the German
university at Bochum such miconceptions were one of our
favourite subsects of study in teaching physics.
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
Ulrich,
I think I am with you, but
let me see wether my simple understanding is correct:
Assuming a object without sensitivity to gravity flying with a
certain (high) speed across space approaching planet terra.
The path of this object would be obviously straight as a line
(as long we are not thinking in astronomical dimensions) , and even
passing the planet in a very short distance, nothing would deviate
this object from this straight way.
If suddenly, only for a short moment, the bypassing object would get
mass, the gravity of both bodys would play its role and accelerate
this mass into direction of the planet, and vice versa. Due to the
immens big mass difference we forget here the orbit or path change
of the planet. The accelerated object does change the direction
somewhat into the planets center of gravity. The amount depends
on the relation between the impulse with direction and the gravitational
impact at that momentary position. After a bend in the path and a
switch off of the object's gravity, the passing object would
continue the straight flight but in a new direction.
As in reality there is no possibilty for such tricks, the approaching object
will receive continuously these deviating gravity impacts, therefore
beeing continuously accelerated to deviate from the linear path
into a orbitical path, if the gravity force is of the right amount, if not
this body will end with an impact or escape after a longer curvature.
Again back on (a new) straight path out of the gravity from
celestial bodys, there are no more other forces acting on this object.
This free flying object does not need any further force or energy to
contiue its way until other forces will stop the way.
Where this object finally did come from, does not change the facts,
this object could have been launched from the planet terra as well,
accelerated sufficiently to end as satellite or as spacevehicle on the
way out of the solar system.
Thinking this way, I could not find any centrifugal forces, active
was only the gravity between this bodys fighting with impuls of the
object. Would this body not just fall down vertically without own
impuls or impetus?
I think the problem thinking on centrifuges is, that the surroundig
object is getting not only the fixation to avoid to escape but as well
the tangential speed / impuls via the coupling and the continuous
acceleration forcing into a circular path.
The outcome should be the same as above.
Just a short analogon for auquatic fans: Driving a ship straight ahaid
with the rudder straight in the middle, the course will be like a line.
Then switching the jet-rudder in the bow on, the water-jet will deviate to
a circular course with the same effects, we do sense the acceleration....
73
Arnold, DK2WT
On Mon, 28 May 2007 21:15:08 +0200, Ulrich Bangert wrote:
>Didier,
>> Since you know a lot more about this than I do, I will accept
>> your statement that centrifugal forces (or more generally
>> inertial forces) are fictitious, but only because you insist.
>> As long as I can predict their effect and calculate their
>> magnitude, that's all this engineer is interested in :-)
>That would be totally wrong! You are just missing the possibility to
>gain some new insights into nature.
>> Your comparison with the linear motion is not valid.
>Please note that my intention was not to immediatly compare linear to
>circle motion. The example was merely to show you something about about
>forces and counterforces. You did not excactly understand it so let me
>try to take a second chance:
>> Inertia causes real forces to be developed.
>If this sentence is true then please answer again the following
>question: Is there a real inertial counterforce in the linear example or
>not?
>73s and my best regards
>Ulrich, DF6JB
>> -----Ursprüngliche Nachricht-----
>> Von: time-nuts-bounces@febo.com
>> [mailto:time-nuts-bounces@febo.com] Im Auftrag von Didier Juges
>> Gesendet: Montag, 28. Mai 2007 17:59
>> An: 'Discussion of precise time and frequency measurement'
>> Betreff: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
>>
>>
>> Ulrich,
>>
>> Your comparison with the linear motion is not valid. While
>> you push the body, it accelerates. The energy spent giving
>> the body increased speed (due to the excess force applied to
>> the body while there is no counter
>> force) is stored in kinetic energy. Once you stop pushing,
>> the body moves straight at constant speed and there is no
>> more force either way, the state of motion does not change.
>>
>> Going back to the satellite, I believe we agree in principal
>> but you are hung up on the first law definition. The
>> corollary to the first law is that objects resist change to
>> their state of motion. They resist that change via inertia.
>> Inertia causes real forces to be developed. I agree it's not
>> a fundamental force like gravity or electromagnetism, but it
>> is necessary to keep the system in equilibrium, otherwise
>> what would be holding the satellite at a constant distance
>> while it is being pulled towards earth?
>>
>> Example: a car is moving at 1m/s. You stand still on the
>> driveway (your
>> speed: 0m/s.) The car hits you. Because the car is much
>> heavier (err: has more mass) than you, you now move at close
>> to 1m/s and the car has just slowed down a bit (m * v stays
>> the same). The car has exerted a force on you that gave you
>> acceleration. You have exerted a force on the car that caused
>> the car to change it's speed, you imparted on the car a
>> certain acceleration in the opposite direction. The only way
>> the car could feel acceleration is because a force was
>> exerted upon it. The force that was exerted on the car came
>> from the inertia of your body. It is a real force. Now,
>> imagine the driveway was itself on a sliding plane moving at
>> 1m/s in the opposite direction to the car. In fact, the car
>> was not moving but you were. It makes no difference, once you
>> realize the only difference is where the reference it. Two
>> forces were developed. Which one you call action and which
>> one is reaction is irrelevant. It's only a matter of
>> reference. Because you change the reference does not make the
>> force go away.
>>
>> We agree on what is happening, we don't agree on what to call it.
>>
>> Since you know a lot more about this than I do, I will accept
>> your statement that centrifugal forces (or more generally
>> inertial forces) are fictitious, but only because you insist.
>> As long as I can predict their effect and calculate their
>> magnitude, that's all this engineer is interested in :-)
>>
>> 73,
>> Didier KO4BB
>>
>>
>> -----Original Message-----
>> From: time-nuts-bounces@febo.com
>> [mailto:time-nuts-bounces@febo.com] On Behalf Of Ulrich Bangert
>> Sent: Monday, May 28, 2007 8:23 AM
>> To: 'Discussion of precise time and frequency measurement'
>> Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
>>
>> Didier,
>>
>> let us consider the more easier case of an linear motion.
>> Imagine an body that can glide on an surface without any
>> friction. Now you take a finger of your hand and press it on
>> one side of the body so that it moves horizontally. Clearly
>> your finger exercises an force on the body that makes it
>> accelerate. And in your finger you feel an force into the
>> opposite direction.
>>
>> The key question is about the physical reality of this force
>> in the opposite direction.
>>
>> How big is it? I guess, you would argument that it has the
>> same magnitude as the force that you apply with your finger
>> but has the opposite direction, right? Now you have TWO
>> forces. If they have the same magnitude but opposite
>> direction their vectors add to zero and I am almost sure you
>> would argument that this makes the sum of forces zero for the system.
>>
>> Now, that you have shown that the sum of forces is zero you
>> are in the ungraceful position in that you must explain why
>> the body IS ACCELERATING at all. According to F=m*a a
>> non-zero F is necessary to generate a non-zero a. How do you explain?
>>
>> Please note that in physics there is one substantial thing
>> that one must know about forces and counterforces: They never
>> affect on the SAME body but always on DIFFERENT bodies. In
>> case you do not believe take the next textbook and read it
>> after. For the above experiment this means: Since BOTH forces
>> that you are talking about affect on the same one body one of
>> the forces CANNOT be the counterforce to the other. If this
>> is so then lets search for the counterforce for the force
>> that you apply with your finger. In order to be able to
>> execute this force your feet or other parts of your body
>> execute an force into opposite direction to the surface of
>> earth. These two forces are counterforces to each other because they
>>
>> a) have opposite directions
>>
>> b) have same magnitude
>>
>> c) apply to different bodies.
>>
>> Now that we have found the counterforce that makes the sum of
>> forces zero for the system you need to find the counterforce
>> to your inertial force and you will find none. Perhaps it is
>> helpful for your understanding that one of the definitions
>> for fictitious forces is that no counterforce belonging to
>> them can be found. And if no counterforce can be found they
>> have NO physical reality because otherwise the rule of the
>> sum of forces is violated.
>>
>> There was only ONE force F acting on the body that make it
>> accelerate according F=m*a and this force had its source in
>> your finger. To be able to execute this force you "pressed
>> against earth" into the opposite direction and that makes the
>> sum of forces zero. This is the only correct physical
>> explanation of this example. ALL forces due to effects of
>> inertia are fictitious forces.
>>
>> 73 and my best regards
>> Ulrich, DF6JB
>>
>> P.S.
>>
>> Newton's first law says that a body at which all forces
>> compensate keeps it current state of motion. To keep the
>> current state of motion a body
>>
>> a) has to keep its velocity
>>
>> and
>>
>> b) has to keep its direction of flight.
>>
>> It this what a satellite does? No, it permanently changes its
>> direction of flight due to earth's gravitational force. If
>> there were compensating forces the satellite would move away
>> along a straight line.
>>
>> Please note: I knew before that this would make a big
>> discussion because the misconception is spread that wide.
>> Perhaps you even learned this at school. When I worked as an
>> "Wissenschaftlicher Mitarbeiter" (comparable to an assistent
>> professor) at the department of physics of the German
>> university at Bochum such miconceptions were one of our
>> favourite subsects of study in teaching physics.
>>
>>
>>
>>
>> _______________________________________________
>> time-nuts mailing list
>> time-nuts@febo.com
>> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
>>
>_______________________________________________
>time-nuts mailing list
>time-nuts@febo.com
>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
DJ
Didier Juges
Mon, May 28, 2007 11:45 PM
Since you know a lot more about this than I do, I will accept
your statement that centrifugal forces (or more generally
inertial forces) are fictitious, but only because you insist.
As long as I can predict their effect and calculate their
magnitude, that's all this engineer is interested in :-)
That would be totally wrong! You are just missing the possibility to
gain some new insights into nature.
Well, I want to understand, but your explanations are not satisfactory.
They support your point but are not an explanation for my observations.
When an object slides on the surface of a table, friction slows it down.
As the object slows down, the supporting table is pushed in the
direction of motion of the object. The force of inertia (the reluctance
of the object to change it's state of motion) pushes the table through
friction. Otherwise, where is the force that is pushing the table coming
from?
Newton's first law, the way I understand it, says that objects resist
changes to their state of motion. If they do not do it through force,
how do you know? Do they turn red and all upset and start yelling like
someone I know?
Now, there is something else I would be missing under your scenario.
When an object is subjected to acceleration, it gains speed. The product
of force by speed is stored in the object in the form of kinetic energy.
If the satellite is constantly being subjected to unbalanced forces and
falls, it should be accelerating and accumulating energy, yet it does
not. 10 years later, a satellite has no more kinetic energy than when it
was launched (if all goes well...) Actually, satellites that are in
elliptical orbits trade kinetic energy for potential energy, just like
the old L-C network constantly trades electrostatic energy for magnetic
energy. But the sum remains constant, except for friction on imperfect
vacuum of space.
So what is it that prevents the satellite that is constantly subjected
to unbalanced forces to not gain speed and energy?
Your comparison with the linear motion is not valid.
Please note that my intention was not to immediatly compare linear to
circle motion. The example was merely to show you something about about
forces and counterforces. You did not excactly understand it so let me
try to take a second chance:
Inertia causes real forces to be developed.
If this sentence is true then please answer again the following
question: Is there a real inertial counterforce in the linear example or
not?
The counterforce is precisely what makes the body resistant to change.
73s and my best regards
Ulrich, DF6JB
Keep trying, I am sure eventually it will make sense...
73,
Didier KO4BB
Ulrich Bangert wrote:
> Didier,
>
>
>> Since you know a lot more about this than I do, I will accept
>> your statement that centrifugal forces (or more generally
>> inertial forces) are fictitious, but only because you insist.
>> As long as I can predict their effect and calculate their
>> magnitude, that's all this engineer is interested in :-)
>>
>
> That would be totally wrong! You are just missing the possibility to
> gain some new insights into nature.
>
>
Well, I want to understand, but your explanations are not satisfactory.
They support your point but are not an explanation for my observations.
When an object slides on the surface of a table, friction slows it down.
As the object slows down, the supporting table is pushed in the
direction of motion of the object. The force of inertia (the reluctance
of the object to change it's state of motion) pushes the table through
friction. Otherwise, where is the force that is pushing the table coming
from?
Newton's first law, the way I understand it, says that objects resist
changes to their state of motion. If they do not do it through force,
how do you know? Do they turn red and all upset and start yelling like
someone I know?
Now, there is something else I would be missing under your scenario.
When an object is subjected to acceleration, it gains speed. The product
of force by speed is stored in the object in the form of kinetic energy.
If the satellite is constantly being subjected to unbalanced forces and
falls, it should be accelerating and accumulating energy, yet it does
not. 10 years later, a satellite has no more kinetic energy than when it
was launched (if all goes well...) Actually, satellites that are in
elliptical orbits trade kinetic energy for potential energy, just like
the old L-C network constantly trades electrostatic energy for magnetic
energy. But the sum remains constant, except for friction on imperfect
vacuum of space.
So what is it that prevents the satellite that is constantly subjected
to unbalanced forces to not gain speed and energy?
>> Your comparison with the linear motion is not valid.
>>
>
> Please note that my intention was not to immediatly compare linear to
> circle motion. The example was merely to show you something about about
> forces and counterforces. You did not excactly understand it so let me
> try to take a second chance:
>
>
>> Inertia causes real forces to be developed.
>>
>
> If this sentence is true then please answer again the following
> question: Is there a real inertial counterforce in the linear example or
> not?
>
>
The counterforce is precisely what makes the body resistant to change.
> 73s and my best regards
> Ulrich, DF6JB
>
Keep trying, I am sure eventually it will make sense...
73,
Didier KO4BB
DB
Dr Bruce Griffiths
Tue, May 29, 2007 4:31 AM
Ulrich, Didier
Talking about forces, gravitational fields etc makes no physical sense
if the observer's reference frame isn't specified.
For an observer in/on a satellite orbiting about the Earth with their
reference frame fixed with respect to the satellite.
There is no gravitational field, whatever methods chosen to measure a
gravitational field (within the satellite) will always produce a null
result.
Pendulum clocks fail to work, given an initial push they will just
rotate around the pivot, provided the pivot suitably constrains the
motion of the pendulum (ie a shaft running in a set of ball or roller
bearings or similar and not a knife edge pivot).
If, however the satellite acts as a rigid body and has a large enough
diameter then it would be possible for an observer on the satellite to
detect a gravitational field gradient.
If the satellite is large enough and orbits close enough to the Earth,
this gravitational field gradient would tear the satellite apart.
For an observer located on the Earth however the motion of the satellite
can be accurately described by Newtonian mechanics where the centripetal
pull of gravity acts on the satellite causing it to have a centripetal
(radial) acceleration as it orbits the Earth.
Bruce
Ulrich, Didier
Talking about forces, gravitational fields etc makes no physical sense
if the observer's reference frame isn't specified.
For an observer in/on a satellite orbiting about the Earth with their
reference frame fixed with respect to the satellite.
There is no gravitational field, whatever methods chosen to measure a
gravitational field (within the satellite) will always produce a null
result.
Pendulum clocks fail to work, given an initial push they will just
rotate around the pivot, provided the pivot suitably constrains the
motion of the pendulum (ie a shaft running in a set of ball or roller
bearings or similar and not a knife edge pivot).
If, however the satellite acts as a rigid body and has a large enough
diameter then it would be possible for an observer on the satellite to
detect a gravitational field gradient.
If the satellite is large enough and orbits close enough to the Earth,
this gravitational field gradient would tear the satellite apart.
For an observer located on the Earth however the motion of the satellite
can be accurately described by Newtonian mechanics where the centripetal
pull of gravity acts on the satellite causing it to have a centripetal
(radial) acceleration as it orbits the Earth.
Bruce
BB
Bill Beam
Tue, May 29, 2007 9:51 AM
On Tue, 29 May 2007 16:31:40 +1200, Dr Bruce Griffiths wrote:
Ulrich, Didier
Talking about forces, gravitational fields etc makes no physical sense
if the observer's reference frame isn't specified.
For an observer in/on a satellite orbiting about the Earth with their
reference frame fixed with respect to the satellite.
There is no gravitational field, whatever methods chosen to measure a
gravitational field (within the satellite) will always produce a null
result.
Not true.
Very simple experiments will show occupants of the satellite that they
are in a non-inertial reference frame. (Release a few test masses
about the cabin and you will observe that they move/accelerate for no
apparent reason, unless the satellite is in free fall which you'll know soon
enough,) The experimenter must conclude that the satellite is undergoing
acceleration due to the influence of an attractive (gravitational) field.
Just because NASA calls it 'microgravity' doesn't make it true. It means
NASA is wrong. Weightlessness is not the same as zero-g.
Pendulum clocks fail to work, given an initial push they will just
rotate around the pivot, provided the pivot suitably constrains the
motion of the pendulum (ie a shaft running in a set of ball or roller
bearings or similar and not a knife edge pivot).
If, however the satellite acts as a rigid body and has a large enough
diameter then it would be possible for an observer on the satellite to
detect a gravitational field gradient.
Therefore, you must conclude that somewhere inside the satellite g is not zero.
If the satellite is large enough and orbits close enough to the Earth,
this gravitational field gradient would tear the satellite apart.
For an observer located on the Earth however the motion of the satellite
can be accurately described by Newtonian mechanics where the centripetal
pull of gravity acts on the satellite causing it to have a centripetal
(radial) acceleration as it orbits the Earth.
Bruce
Regards,
Bill Beam (PhD, physics 1966, past tenured Associate Professor of Physics)
Bill Beam
NL7F
--
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.467 / Virus Database: 269.8.0/818 - Release Date: 5/25/2007 12:32 PM
On Tue, 29 May 2007 16:31:40 +1200, Dr Bruce Griffiths wrote:
>Ulrich, Didier
>
>Talking about forces, gravitational fields etc makes no physical sense
>if the observer's reference frame isn't specified.
>For an observer in/on a satellite orbiting about the Earth with their
>reference frame fixed with respect to the satellite.
>There is no gravitational field, whatever methods chosen to measure a
>gravitational field (within the satellite) will always produce a null
>result.
Not true.
Very simple experiments will show occupants of the satellite that they
are in a non-inertial reference frame. (Release a few test masses
about the cabin and you will observe that they move/accelerate for no
apparent reason, unless the satellite is in free fall which you'll know soon
enough,) The experimenter must conclude that the satellite is undergoing
acceleration due to the influence of an attractive (gravitational) field.
Just because NASA calls it 'microgravity' doesn't make it true. It means
NASA is wrong. Weightlessness is not the same as zero-g.
>Pendulum clocks fail to work, given an initial push they will just
>rotate around the pivot, provided the pivot suitably constrains the
>motion of the pendulum (ie a shaft running in a set of ball or roller
>bearings or similar and not a knife edge pivot).
>
>If, however the satellite acts as a rigid body and has a large enough
>diameter then it would be possible for an observer on the satellite to
>detect a gravitational field gradient.
Therefore, you must conclude that somewhere inside the satellite g is not zero.
>If the satellite is large enough and orbits close enough to the Earth,
>this gravitational field gradient would tear the satellite apart.
>
>For an observer located on the Earth however the motion of the satellite
>can be accurately described by Newtonian mechanics where the centripetal
>pull of gravity acts on the satellite causing it to have a centripetal
>(radial) acceleration as it orbits the Earth.
>
>
>Bruce
>
Regards,
Bill Beam (PhD, physics 1966, past tenured Associate Professor of Physics)
Bill Beam
NL7F
--
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.467 / Virus Database: 269.8.0/818 - Release Date: 5/25/2007 12:32 PM
DB
Dr Bruce Griffiths
Tue, May 29, 2007 10:27 AM
On Tue, 29 May 2007 16:31:40 +1200, Dr Bruce Griffiths wrote:
Ulrich, Didier
Talking about forces, gravitational fields etc makes no physical sense
if the observer's reference frame isn't specified.
For an observer in/on a satellite orbiting about the Earth with their
reference frame fixed with respect to the satellite.
There is no gravitational field, whatever methods chosen to measure a
gravitational field (within the satellite) will always produce a null
result.
Not true.
Very simple experiments will show occupants of the satellite that they
are in a non-inertial reference frame. (Release a few test masses
about the cabin and you will observe that they move/accelerate for no
apparent reason, unless the satellite is in free fall which you'll know soon
enough,) The experimenter must conclude that the satellite is undergoing
acceleration due to the influence of an attractive (gravitational) field.
Just because NASA calls it 'microgravity' doesn't make it true. It means
NASA is wrong. Weightlessness is not the same as zero-g.
Only, if you insist on sticking to Newtonian physics with all its
attendant problems.
Pendulum clocks fail to work, given an initial push they will just
rotate around the pivot, provided the pivot suitably constrains the
motion of the pendulum (ie a shaft running in a set of ball or roller
bearings or similar and not a knife edge pivot).
If, however the satellite acts as a rigid body and has a large enough
diameter then it would be possible for an observer on the satellite to
detect a gravitational field gradient.
Therefore, you must conclude that somewhere inside the satellite g is not zero.
A finite gradient doesn't imply that the field itself is nonzero, except
of course towards the extremeities of the satellite.
Regards,
Bill Beam (PhD, physics 1966, past tenured Associate Professor of Physics)
Bill Beam
NL7F
Bill
Bill Beam wrote:
> On Tue, 29 May 2007 16:31:40 +1200, Dr Bruce Griffiths wrote:
>
>
>> Ulrich, Didier
>>
>> Talking about forces, gravitational fields etc makes no physical sense
>> if the observer's reference frame isn't specified.
>> For an observer in/on a satellite orbiting about the Earth with their
>> reference frame fixed with respect to the satellite.
>> There is no gravitational field, whatever methods chosen to measure a
>> gravitational field (within the satellite) will always produce a null
>> result.
>>
>
> Not true.
> Very simple experiments will show occupants of the satellite that they
> are in a non-inertial reference frame. (Release a few test masses
> about the cabin and you will observe that they move/accelerate for no
> apparent reason, unless the satellite is in free fall which you'll know soon
> enough,) The experimenter must conclude that the satellite is undergoing
> acceleration due to the influence of an attractive (gravitational) field.
>
> Just because NASA calls it 'microgravity' doesn't make it true. It means
> NASA is wrong. Weightlessness is not the same as zero-g.
>
>
Only, if you insist on sticking to Newtonian physics with all its
attendant problems.
>> Pendulum clocks fail to work, given an initial push they will just
>> rotate around the pivot, provided the pivot suitably constrains the
>> motion of the pendulum (ie a shaft running in a set of ball or roller
>> bearings or similar and not a knife edge pivot).
>>
>> If, however the satellite acts as a rigid body and has a large enough
>> diameter then it would be possible for an observer on the satellite to
>> detect a gravitational field gradient.
>>
>
> Therefore, you must conclude that somewhere inside the satellite g is not zero.
>
>
A finite gradient doesn't imply that the field itself is nonzero, except
of course towards the extremeities of the satellite.
>
> Regards,
> Bill Beam (PhD, physics 1966, past tenured Associate Professor of Physics)
>
>
> Bill Beam
> NL7F
>
>
>
Bruce
BB
Bill Beam
Tue, May 29, 2007 2:08 PM
On Tue, 29 May 2007 22:27:42 +1200, Dr Bruce Griffiths wrote:
On Tue, 29 May 2007 16:31:40 +1200, Dr Bruce Griffiths wrote:
Ulrich, Didier
Talking about forces, gravitational fields etc makes no physical sense
if the observer's reference frame isn't specified.
For an observer in/on a satellite orbiting about the Earth with their
reference frame fixed with respect to the satellite.
There is no gravitational field, whatever methods chosen to measure a
gravitational field (within the satellite) will always produce a null
result.
Not true.
Very simple experiments will show occupants of the satellite that they
are in a non-inertial reference frame. (Release a few test masses
about the cabin and you will observe that they move/accelerate for no
apparent reason, unless the satellite is in free fall which you'll know soon
enough,) The experimenter must conclude that the satellite is undergoing
acceleration due to the influence of an attractive (gravitational) field.
Just because NASA calls it 'microgravity' doesn't make it true. It means
NASA is wrong. Weightlessness is not the same as zero-g.
Only, if you insist on sticking to Newtonian physics with all its
attendant problems.
This discussion began as a classical problem. The relativistic effects
are many orders of magnitude smaller than Newtonian (v/c=2.6e-5).
For example: A test mass released on the Earth side of the satellite
cabin will advance in its own orbit a few mm/sec faster than one released
on the far side due to purely classical differences in orbits. Easily observable
without even using a timepiece.
Once your feet leave the ground, not even Newtonian mechanics is
intuitive. Who would have thought that 'putting on the brakes' to
leave orbit would cause a satellite to speed up....
Pendulum clocks fail to work, given an initial push they will just
rotate around the pivot, provided the pivot suitably constrains the
motion of the pendulum (ie a shaft running in a set of ball or roller
bearings or similar and not a knife edge pivot).
Run the numbers - depends on how hard the push.
Consider sheeparding of material in Saturn rings by small moons.
If, however the satellite acts as a rigid body and has a large enough
diameter then it would be possible for an observer on the satellite to
detect a gravitational field gradient.
Therefore, you must conclude that somewhere inside the satellite g is not zero.
A finite gradient doesn't imply that the field itself is nonzero, except
of course towards the extremeities of the satellite.
Of course it does.
If g=0 everywhere in the neighborhood of a point then the gradient is zero.
Else, what is the meaning of gradient?
Grad not zero implies field not uniform implies not(field zero everywhere).
Regards,
Bill Beam (PhD, physics 1966, past tenured Associate Professor of Physics)
Bill Beam
NL7F
Bill Beam
NL7F
--
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.467 / Virus Database: 269.8.0/818 - Release Date: 5/25/2007 12:32 PM
On Tue, 29 May 2007 22:27:42 +1200, Dr Bruce Griffiths wrote:
>Bill
>Bill Beam wrote:
>> On Tue, 29 May 2007 16:31:40 +1200, Dr Bruce Griffiths wrote:
>>
>>
>>> Ulrich, Didier
>>>
>>> Talking about forces, gravitational fields etc makes no physical sense
>>> if the observer's reference frame isn't specified.
>>> For an observer in/on a satellite orbiting about the Earth with their
>>> reference frame fixed with respect to the satellite.
>>> There is no gravitational field, whatever methods chosen to measure a
>>> gravitational field (within the satellite) will always produce a null
>>> result.
>>>
>>
>> Not true.
>> Very simple experiments will show occupants of the satellite that they
>> are in a non-inertial reference frame. (Release a few test masses
>> about the cabin and you will observe that they move/accelerate for no
>> apparent reason, unless the satellite is in free fall which you'll know soon
>> enough,) The experimenter must conclude that the satellite is undergoing
>> acceleration due to the influence of an attractive (gravitational) field.
>>
>> Just because NASA calls it 'microgravity' doesn't make it true. It means
>> NASA is wrong. Weightlessness is not the same as zero-g.
>>
>>
>Only, if you insist on sticking to Newtonian physics with all its
>attendant problems.
This discussion began as a classical problem. The relativistic effects
are many orders of magnitude smaller than Newtonian (v/c=2.6e-5).
For example: A test mass released on the Earth side of the satellite
cabin will advance in its own orbit a few mm/sec faster than one released
on the far side due to purely classical differences in orbits. Easily observable
without even using a timepiece.
Once your feet leave the ground, not even Newtonian mechanics is
intuitive. Who would have thought that 'putting on the brakes' to
leave orbit would cause a satellite to speed up....
>
>>> Pendulum clocks fail to work, given an initial push they will just
>>> rotate around the pivot, provided the pivot suitably constrains the
>>> motion of the pendulum (ie a shaft running in a set of ball or roller
>>> bearings or similar and not a knife edge pivot).
Run the numbers - depends on how hard the push.
Consider sheeparding of material in Saturn rings by small moons.
>>>
>>> If, however the satellite acts as a rigid body and has a large enough
>>> diameter then it would be possible for an observer on the satellite to
>>> detect a gravitational field gradient.
>>>
>>
>> Therefore, you must conclude that somewhere inside the satellite g is not zero.
>>
>>
>A finite gradient doesn't imply that the field itself is nonzero, except
>of course towards the extremeities of the satellite.
Of course it does.
If g=0 everywhere in the neighborhood of a point then the gradient is zero.
Else, what is the meaning of gradient?
Grad not zero implies field not uniform implies not(field zero everywhere).
>>
>> Regards,
>> Bill Beam (PhD, physics 1966, past tenured Associate Professor of Physics)
>>
>>
>> Bill Beam
>> NL7F
>>
>>
>>
>Bruce
>
>
>_______________________________________________
>time-nuts mailing list
>time-nuts@febo.com
>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Bill Beam
NL7F
--
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.467 / Virus Database: 269.8.0/818 - Release Date: 5/25/2007 12:32 PM
DB
Dr Bruce Griffiths
Wed, May 30, 2007 12:10 AM
Not true.
Very simple experiments will show occupants of the satellite that they
are in a non-inertial reference frame. (Release a few test masses
about the cabin and you will observe that they move/accelerate for no
apparent reason, unless the satellite is in free fall which you'll know soon
enough,) The experimenter must conclude that the satellite is undergoing
acceleration due to the influence of an attractive (gravitational) field.
Just because NASA calls it 'microgravity' doesn't make it true. It means
NASA is wrong. Weightlessness is not the same as zero-g.
Only, if you insist on sticking to Newtonian physics with all its
attendant problems.
This discussion began as a classical problem. The relativistic effects
are many orders of magnitude smaller than Newtonian (v/c=2.6e-5).
For example: A test mass released on the Earth side of the satellite
cabin will advance in its own orbit a few mm/sec faster than one released
on the far side due to purely classical differences in orbits. Easily observable
without even using a timepiece.
Once your feet leave the ground, not even Newtonian mechanics is
intuitive. Who would have thought that 'putting on the brakes' to
leave orbit would cause a satellite to speed up....
The existence of "privileged" frames of reference in Newtonian mechanics
and special relativity has always seemed problematic, especially when it
may be observationally difficult to identify such a frame of reference.
Fortunately the inertial reference frames are not imbued with the same
privileges by general relativity.
Pendulum clocks fail to work, given an initial push they will just
rotate around the pivot, provided the pivot suitably constrains the
motion of the pendulum (ie a shaft running in a set of ball or roller
bearings or similar and not a knife edge pivot).
Run the numbers - depends on how hard the push.
Consider sheeparding of material in Saturn rings by small moons.
Surely the forces involved are impractically low for a real pendulum.
A finite gradient doesn't imply that the field itself is nonzero, except
of course towards the extremeities of the satellite.
Of course it does.
If g=0 everywhere in the neighborhood of a point then the gradient is zero.
Else, what is the meaning of gradient?
Grad not zero implies field not uniform implies not(field zero everywhere).
I should have been more explicit I meant a finite gradient at a point
does not imply the field is no zero at that point.Bill Beam
Bruce
Bill Beam wrote:
>>> Not true.
>>> Very simple experiments will show occupants of the satellite that they
>>> are in a non-inertial reference frame. (Release a few test masses
>>> about the cabin and you will observe that they move/accelerate for no
>>> apparent reason, unless the satellite is in free fall which you'll know soon
>>> enough,) The experimenter must conclude that the satellite is undergoing
>>> acceleration due to the influence of an attractive (gravitational) field.
>>>
>>> Just because NASA calls it 'microgravity' doesn't make it true. It means
>>> NASA is wrong. Weightlessness is not the same as zero-g.
>>>
>>>
>>>
>> Only, if you insist on sticking to Newtonian physics with all its
>> attendant problems.
>>
>
> This discussion began as a classical problem. The relativistic effects
> are many orders of magnitude smaller than Newtonian (v/c=2.6e-5).
> For example: A test mass released on the Earth side of the satellite
> cabin will advance in its own orbit a few mm/sec faster than one released
> on the far side due to purely classical differences in orbits. Easily observable
> without even using a timepiece.
>
> Once your feet leave the ground, not even Newtonian mechanics is
> intuitive. Who would have thought that 'putting on the brakes' to
> leave orbit would cause a satellite to speed up....
>
>
The existence of "privileged" frames of reference in Newtonian mechanics
and special relativity has always seemed problematic, especially when it
may be observationally difficult to identify such a frame of reference.
Fortunately the inertial reference frames are not imbued with the same
privileges by general relativity.
>>>> Pendulum clocks fail to work, given an initial push they will just
>>>> rotate around the pivot, provided the pivot suitably constrains the
>>>> motion of the pendulum (ie a shaft running in a set of ball or roller
>>>> bearings or similar and not a knife edge pivot).
>>>>
>
> Run the numbers - depends on how hard the push.
> Consider sheeparding of material in Saturn rings by small moons.
>
>
Surely the forces involved are impractically low for a real pendulum.
>> A finite gradient doesn't imply that the field itself is nonzero, except
>> of course towards the extremeities of the satellite.
>>
>
> Of course it does.
>
> If g=0 everywhere in the neighborhood of a point then the gradient is zero.
> Else, what is the meaning of gradient?
>
> Grad not zero implies field not uniform implies not(field zero everywhere).
>
>
I should have been more explicit I meant a finite gradient at a point
does not imply the field is no zero at that point.Bill Beam
Bruce
DB
Dr Bruce Griffiths
Wed, May 30, 2007 12:49 AM
Not true.
Very simple experiments will show occupants of the satellite that they
are in a non-inertial reference frame. (Release a few test masses
about the cabin and you will observe that they move/accelerate for no
apparent reason, unless the satellite is in free fall which you'll know soon
enough,) The experimenter must conclude that the satellite is undergoing
acceleration due to the influence of an attractive (gravitational) field.
Except when released at rest with respect to the satellites centre of
mass the test masses will both drift towards the satellites centre of mass.
The outermost test mass will have too slow an orbital speed to remain at
the position it was released and the innermost test mass will have too
large an orbital speed to remain at the position at which it was released.
Bruce
Bill Beam wrote:
>>> Not true.
>>> Very simple experiments will show occupants of the satellite that they
>>> are in a non-inertial reference frame. (Release a few test masses
>>> about the cabin and you will observe that they move/accelerate for no
>>> apparent reason, unless the satellite is in free fall which you'll know soon
>>> enough,) The experimenter must conclude that the satellite is undergoing
>>> acceleration due to the influence of an attractive (gravitational) field.
>>>
>>>
Except when released at rest with respect to the satellites centre of
mass the test masses will both drift towards the satellites centre of mass.
The outermost test mass will have too slow an orbital speed to remain at
the position it was released and the innermost test mass will have too
large an orbital speed to remain at the position at which it was released.
Bruce
DC
Don Collie
Wed, May 30, 2007 7:21 AM
Its just like the fly in the glass jar scenarmino : Just imagine a glass jar [with a lid] with a fly flying around inside the jar. The jar is being accelerated towards its inevitable demise when it hits the sun. Does the
fly stay in the same position in the jar, or is it "pushed" towards the end
of the jar furtheest from the sun. Now I dont know the answer to this one..........but I sure wouldnt like to bee the fly.
Affectionately yours,...............Don Collie jnr.
----- Original Message -----
From: "Dr Bruce Griffiths" bruce.griffiths@xtra.co.nz
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Wednesday, May 30, 2007 12:49 PM
Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Not true.
Very simple experiments will show occupants of the satellite that they
are in a non-inertial reference frame. (Release a few test masses
about the cabin and you will observe that they move/accelerate for no
apparent reason, unless the satellite is in free fall which you'll know
soon
enough,) The experimenter must conclude that the satellite is
undergoing
acceleration due to the influence of an attractive (gravitational)
field.
Except when released at rest with respect to the satellites centre of
mass the test masses will both drift towards the satellites centre of
mass.
The outermost test mass will have too slow an orbital speed to remain at
the position it was released and the innermost test mass will have too
large an orbital speed to remain at the position at which it was released.
Bruce
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.472 / Virus Database: 269.8.1/822 - Release Date: 5/28/2007
11:40 AM
It`s just like the fly in the glass jar scenarmino : Just imagine a glass
jar [with a lid] with a fly flying around inside the jar. The jar is being
accelerated towards it`s inevitable demise when it hits the sun. Does the
fly stay in the same position in the jar, or is it "pushed" towards the end
of the jar furtheest from the sun. Now I don`t know the answer to this
one..........but I sure wouldn`t like to bee the fly.
Affectionately yours,...............Don Collie jnr.
----- Original Message -----
From: "Dr Bruce Griffiths" <bruce.griffiths@xtra.co.nz>
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Sent: Wednesday, May 30, 2007 12:49 PM
Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
> Bill Beam wrote:
>
>
>
>>>> Not true.
>>>> Very simple experiments will show occupants of the satellite that they
>>>> are in a non-inertial reference frame. (Release a few test masses
>>>> about the cabin and you will observe that they move/accelerate for no
>>>> apparent reason, unless the satellite is in free fall which you'll know
>>>> soon
>>>> enough,) The experimenter must conclude that the satellite is
>>>> undergoing
>>>> acceleration due to the influence of an attractive (gravitational)
>>>> field.
>>>>
>>>>
> Except when released at rest with respect to the satellites centre of
> mass the test masses will both drift towards the satellites centre of
> mass.
> The outermost test mass will have too slow an orbital speed to remain at
> the position it was released and the innermost test mass will have too
> large an orbital speed to remain at the position at which it was released.
>
>
> Bruce
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.472 / Virus Database: 269.8.1/822 - Release Date: 5/28/2007
> 11:40 AM
>
>
BB
Bill Beam
Wed, May 30, 2007 9:10 AM
----- Original Message -----
From: "Dr Bruce Griffiths" bruce.griffiths@xtra.co.nz
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Wednesday, May 30, 2007 12:49 PM
Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
Not true.
Very simple experiments will show occupants of the satellite that they
are in a non-inertial reference frame. (Release a few test masses
about the cabin and you will observe that they move/accelerate for no
apparent reason, unless the satellite is in free fall which you'll know
soon
enough,) The experimenter must conclude that the satellite is
undergoing
acceleration due to the influence of an attractive (gravitational)
field.
Except when released at rest with respect to the satellites centre of
mass the test masses will both drift towards the satellites centre of
mass.
The outermost test mass will have too slow an orbital speed to remain at
the position it was released and the innermost test mass will have too
large an orbital speed to remain at the position at which it was released.
Bruce
Again, this is not true.
Assume satellite in circular orbit. (Not really necessary.)
Assume test mass's released at rest wrt satellite center of mass.
Inner test mass released closer to Earth and outer released farther
from Earth. Also assume no air currents, no relativity, no luminiferous
ether, no static, no s- -t.
The inner test mass will at the time of release have too small a tangential speed
to maintain a circular orbit. It will be at apogee of a slightly elliptical orbit. One
half orbit later it will be at perigee with a slightly increased speed. One full
orbit after release the test mass will be back at apogee and will have drifted
toward the front of the cabin. It will be seen to oscillate toword and away from
the Earth with a period slightly less then the satellite and it will slowly get ahead
of the satellite.
The outer test mass will at the time of release have too large a tangential speed
to maintain a circular orbit. It will be at perigee of a slightly elliptical orbit. One
half orbit later it will be at apogee with a slightly decreased speed. One full
orbit after release the test mass will be back at perigee and will have drifted
toward the rear of the cabin. It will be seen to oscillate away from and toword
the Earth with a period slightly larger then the satellite and it will slowly fall
behind the satellite.
It helps if this problem is solved in a proper (Earth based) inertial frame
and to consider the total energy (kinetic plus potential) of the test masses.
Clearly a satellite based frame is non inertial and therefore Newtons laws
of motion are not valid.
Gentlemen: Those of you who have never taken a university physics course
are excused for confusion over centripital/centrifugal/psudo forces. Some of
you who did take a university physics class spent too much time asleep in
class.
Regards,
Bill Beam
NL7F
--
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.467 / Virus Database: 269.8.0/818 - Release Date: 5/25/2007 12:32 PM
>
>----- Original Message -----
>From: "Dr Bruce Griffiths" <bruce.griffiths@xtra.co.nz>
>To: "Discussion of precise time and frequency measurement"
><time-nuts@febo.com>
>Sent: Wednesday, May 30, 2007 12:49 PM
>Subject: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
>
>
>> Bill Beam wrote:
>>
>>
>>
>>>>> Not true.
>>>>> Very simple experiments will show occupants of the satellite that they
>>>>> are in a non-inertial reference frame. (Release a few test masses
>>>>> about the cabin and you will observe that they move/accelerate for no
>>>>> apparent reason, unless the satellite is in free fall which you'll know
>>>>> soon
>>>>> enough,) The experimenter must conclude that the satellite is
>>>>> undergoing
>>>>> acceleration due to the influence of an attractive (gravitational)
>>>>> field.
>>>>>
>>>>>
>> Except when released at rest with respect to the satellites centre of
>> mass the test masses will both drift towards the satellites centre of
>> mass.
>> The outermost test mass will have too slow an orbital speed to remain at
>> the position it was released and the innermost test mass will have too
>> large an orbital speed to remain at the position at which it was released.
>>
>>
>> Bruce
>>
Again, this is not true.
Assume satellite in circular orbit. (Not really necessary.)
Assume test mass's released at rest wrt satellite center of mass.
Inner test mass released closer to Earth and outer released farther
from Earth. Also assume no air currents, no relativity, no luminiferous
ether, no static, no s- -t.
The inner test mass will at the time of release have too small a tangential speed
to maintain a circular orbit. It will be at apogee of a slightly elliptical orbit. One
half orbit later it will be at perigee with a slightly increased speed. One full
orbit after release the test mass will be back at apogee and will have drifted
toward the front of the cabin. It will be seen to oscillate toword and away from
the Earth with a period slightly less then the satellite and it will slowly get ahead
of the satellite.
The outer test mass will at the time of release have too large a tangential speed
to maintain a circular orbit. It will be at perigee of a slightly elliptical orbit. One
half orbit later it will be at apogee with a slightly decreased speed. One full
orbit after release the test mass will be back at perigee and will have drifted
toward the rear of the cabin. It will be seen to oscillate away from and toword
the Earth with a period slightly larger then the satellite and it will slowly fall
behind the satellite.
It helps if this problem is solved in a proper (Earth based) inertial frame
and to consider the total energy (kinetic plus potential) of the test masses.
Clearly a satellite based frame is non inertial and therefore Newtons laws
of motion are not valid.
Gentlemen: Those of you who have never taken a university physics course
are excused for confusion over centripital/centrifugal/psudo forces. Some of
you who did take a university physics class spent too much time asleep in
class.
Regards,
Bill Beam
NL7F
--
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.467 / Virus Database: 269.8.0/818 - Release Date: 5/25/2007 12:32 PM
DB
Dr Bruce Griffiths
Wed, May 30, 2007 1:52 PM
It helps if this problem is solved in a proper (Earth based) inertial frame
and to consider the total energy (kinetic plus potential) of the test masses.
But there are no strictly inertial frames based on the Earth.
The earth rotates around its axis (neglecting precession, nutation etc),
it also orbits the sun which in turn ...
An actual test of these predictions would be somewhat expensive to carry
out.
The damping due to the air in the shuttle or ISS (as well as a host of
other small effects) would tend to damp out such motion.
The question is how quickly?
Clearly a satellite based frame is non inertial and therefore Newtons laws
of motion are not valid.
Gentlemen: Those of you who have never taken a university physics course
are excused for confusion over centripital/centrifugal/psudo forces. Some of
you who did take a university physics class spent too much time asleep in
class.
Regards,
Bill Beam
NL7F
Bill Beam wrote:
> It helps if this problem is solved in a proper (Earth based) inertial frame
> and to consider the total energy (kinetic plus potential) of the test masses.
>
But there are no strictly inertial frames based on the Earth.
The earth rotates around its axis (neglecting precession, nutation etc),
it also orbits the sun which in turn ...
An actual test of these predictions would be somewhat expensive to carry
out.
The damping due to the air in the shuttle or ISS (as well as a host of
other small effects) would tend to damp out such motion.
The question is how quickly?
> Clearly a satellite based frame is non inertial and therefore Newtons laws
> of motion are not valid.
>
> Gentlemen: Those of you who have never taken a university physics course
> are excused for confusion over centripital/centrifugal/psudo forces. Some of
> you who did take a university physics class spent too much time asleep in
> class.
>
> Regards,
>
> Bill Beam
> NL7F
>
NJ
Neon John
Wed, May 30, 2007 7:17 PM
On Wed, 30 May 2007 01:10:02 -0800, Bill Beam wbeam@gci.net wrote:
Gentlemen: Those of you who have never taken a university physics course
are excused for confusion over centripital/centrifugal/psudo forces. Some of
you who did take a university physics class spent too much time asleep in
class.
I did and I paid attention and I didn't smoke anything I wasn't supposed to but I
don't remember this aspect. This is a learning experience.
John
John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
fas-cism (fash'iz'em) n. A system of government that exercises a
dictatorship of the extreme right, typically through the
merging of state and business leadership, together
with belligerent nationalism. -- The American Heritage Dictionary, 1983
On Wed, 30 May 2007 01:10:02 -0800, Bill Beam <wbeam@gci.net> wrote:
>Gentlemen: Those of you who have never taken a university physics course
>are excused for confusion over centripital/centrifugal/psudo forces. Some of
>you who did take a university physics class spent too much time asleep in
>class.
I did and I paid attention and I didn't smoke anything I wasn't supposed to but I
don't remember this aspect. This is a learning experience.
John
---
John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
*fas-cism* (fash'iz'em) n. A system of government that exercises a
dictatorship of the extreme right, typically through the
merging of state and business leadership, together
with belligerent nationalism. -- The American Heritage Dictionary, 1983
UB
Ulrich Bangert
Wed, May 30, 2007 8:04 PM
I did and I paid attention and I didn't smoke anything I
wasn't supposed to...
Just in case you forgot to mention: What was your favourite drink at
these times?
I really enjoy being part of time-nuts for this exclusive combination of
severe scientific stuff with humor like that which is not so easy to be
found at other places.
Regards
Ulrich Bangert
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Neon John
Gesendet: Mittwoch, 30. Mai 2007 21:18
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
On Wed, 30 May 2007 01:10:02 -0800, Bill Beam wbeam@gci.net wrote:
Gentlemen: Those of you who have never taken a university physics
course are excused for confusion over centripital/centrifugal/psudo
forces. Some of you who did take a university physics class
much time asleep in class.
I did and I paid attention and I didn't smoke anything I
wasn't supposed to but I don't remember this aspect. This is
a learning experience.
John
John De Armond
See my website for my current email address
http://www.neon-john.com Cleveland, Occupied > TN
fas-cism
(fash'iz'em) n. A system of government that exercises a
dictatorship of the extreme right, typically through the
merging of state and business leadership, together
with belligerent nationalism. -- The American Heritage
Dictionary, 1983
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
John,
> I did and I paid attention and I didn't smoke anything I
> wasn't supposed to...
Just in case you forgot to mention: What was your favourite drink at
these times?
I really enjoy being part of time-nuts for this exclusive combination of
severe scientific stuff with humor like that which is not so easy to be
found at other places.
Regards
Ulrich Bangert
> -----Ursprüngliche Nachricht-----
> Von: time-nuts-bounces@febo.com
> [mailto:time-nuts-bounces@febo.com] Im Auftrag von Neon John
> Gesendet: Mittwoch, 30. Mai 2007 21:18
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] FW: Pendulums & Atomic Clocks & Gravity
>
>
> On Wed, 30 May 2007 01:10:02 -0800, Bill Beam <wbeam@gci.net> wrote:
>
>
> >Gentlemen: Those of you who have never taken a university physics
> >course are excused for confusion over centripital/centrifugal/psudo
> >forces. Some of you who did take a university physics class
> spent too
> >much time asleep in class.
>
> I did and I paid attention and I didn't smoke anything I
> wasn't supposed to but I don't remember this aspect. This is
> a learning experience.
>
> John
> ---
> John De Armond
> See my website for my current email address
> http://www.neon-john.com Cleveland, Occupied > TN
>
> *fas-cism*
> (fash'iz'em) n. A system of government that exercises a
> dictatorship of the extreme right, typically through the
> merging of state and business leadership, together
> with belligerent nationalism. -- The American Heritage
> Dictionary, 1983
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
>
BB
Bill Beam
Wed, May 30, 2007 10:12 PM
On Thu, 31 May 2007 01:52:34 +1200, Dr Bruce Griffiths wrote:
Assume satellite in circular orbit. (Not really necessary.)
Assume test mass's released at rest wrt satellite center of mass.
Inner test mass released closer to Earth and outer released farther
from Earth. Also assume no air currents, no relativity, no luminiferous
ether, no static, no s- -t.
It helps if this problem is solved in a proper (Earth based) inertial frame
and to consider the total energy (kinetic plus potential) of the test masses.
But there are no strictly inertial frames based on the Earth.
The earth rotates around its axis (neglecting precession, nutation etc),
it also orbits the sun which in turn ...
An actual test of these predictions would be somewhat expensive to carry
out.
The damping due to the air in the shuttle or ISS (as well as a host of
other small effects) would tend to damp out such motion.
The question is how quickly?
This contradicts the last assumption stated above.
Clearly a satellite based frame is non inertial and therefore Newtons laws
of motion are not valid.
Gentlemen: Those of you who have never taken a university physics course
are excused for confusion over centripital/centrifugal/psudo forces. Some of
you who did take a university physics class spent too much time asleep in
class.
Regards,
Bill Beam
NL7F
Bill Beam
NL7F
--
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.467 / Virus Database: 269.8.0/818 - Release Date: 5/25/2007 12:32 PM
On Thu, 31 May 2007 01:52:34 +1200, Dr Bruce Griffiths wrote:
>Bill Beam wrote:
>>Assume satellite in circular orbit. (Not really necessary.)
>>Assume test mass's released at rest wrt satellite center of mass.
>>Inner test mass released closer to Earth and outer released farther
>>from Earth. Also assume no air currents, no relativity, no luminiferous
>>ether, no static, no s- -t.
>> It helps if this problem is solved in a proper (Earth based) inertial frame
>> and to consider the total energy (kinetic plus potential) of the test masses.
>>
>
>But there are no strictly inertial frames based on the Earth.
>The earth rotates around its axis (neglecting precession, nutation etc),
>it also orbits the sun which in turn ...
>An actual test of these predictions would be somewhat expensive to carry
>out.
>The damping due to the air in the shuttle or ISS (as well as a host of
>other small effects) would tend to damp out such motion.
>The question is how quickly?
This contradicts the last assumption stated above.
>> Clearly a satellite based frame is non inertial and therefore Newtons laws
>> of motion are not valid.
>>
>> Gentlemen: Those of you who have never taken a university physics course
>> are excused for confusion over centripital/centrifugal/psudo forces. Some of
>> you who did take a university physics class spent too much time asleep in
>> class.
>>
>> Regards,
>>
>> Bill Beam
>> NL7F
>>
>
>
>_______________________________________________
>time-nuts mailing list
>time-nuts@febo.com
>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Bill Beam
NL7F
--
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.467 / Virus Database: 269.8.0/818 - Release Date: 5/25/2007 12:32 PM
