[time-nuts] FW: Pendulums & Atomic Clocks & Gravity
wbeam at gci.net
Wed May 30 05:10:02 EDT 2007
>----- Original Message -----
>From: "Dr Bruce Griffiths" <bruce.griffiths at xtra.co.nz>
>To: "Discussion of precise time and frequency measurement"
><time-nuts at 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
>>>>> enough,) The experimenter must conclude that the satellite is
>>>>> acceleration due to the influence of an attractive (gravitational)
>> Except when released at rest with respect to the satellites centre of
>> mass the test masses will both drift towards the satellites centre of
>> 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.
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
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