Re: Inertial Frames

["A. R. Marlow" <marlow@beta.loyno.edu>]

On Wed, 1 May 1996, Chris Jones wrote:
> ...
> By the way, the argument on non-inertial frames has gone on long enough. The 
> effects seem to be agreed, but now the correspondance is just quibbling over 
> definitions. Sort it out!
>
> :-) 


It has gone on long  --  whether long enough is another matter.  If all
that were involved were simply definitions and names, e. g., whether someone
wants to use the symbols F, F', F'' for every mass x acceleration term that
crops up and call them pseudoforces, then I would agree that it has no more
importance than if someone ideosyncratically insisted on referring to 
meteors as pseudocomets.  

However, I believe much more serious issues of misinformation and 
misconception are at stake, which should be tracked down when they
occur on any discussion list that purports to deal with the venerable
and respected subject of astronomy, and that's what is in the process 
of being sorted out.  

For example, the kinematical quantities position, velocity and acceleration,
so vital to astronomy, all obviously and intrinsically involve for their
very definition the specification of some positional frame of reference.
We have at last come to agreement that the dynamical quantities force,
energy do not require such:  I can use a spring scale for force, and I do
not have to look out any window to measure energy exchanges.  Progress is
being made.  We can now reasonably begin to ask whether Newton's laws (or
Einsteinian corrections to such) correctly predict the measured values
of the dynamical quantities if any arbitrary reference frame is allowed
for the measuring of the kinematical data, or if a restricted class of 
frames (inertial frames) is required for the kinematica data to give 
accurate predictions of the dynamical measurements.  It is being gradually
sorted out and it is important.

A. R. Marlow                          E-MAIL:  marlow@beta.loyno.edu
Department of Physics                 PHONE:   (504) 865 3647  (Office)  
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