Re: [Phys-l] Rest energy

[Moses Fayngold <moshfarlan@yahoo.com>]

James Espinosa wrote on Tue, October 26, 2010 11:58:56 AM:

> Some physicists cannot give up the term "rest mass;" which should then require 
> the term "moving mass," even though there is only one value for "mass" between 
> any two >inertial frames.  

  Some physicists cannot give up the term "rest mass" for a good reason, because 
there exist well-known experimentally executable procedures of mass measurement 
which give DIFFERENT RESULTS for mass at rest and mass in motion. No amount of 
words can undermine the ultimate judgement of the experiment.
  No physicist (at least to my knowledge) has ever used the term "rest charge", 
and also for a good reason, because all known experimental procedures of charge 
measurement showed NO DIFFERENCE between the amount of charge at rest and in 
motion.
     
> The term "rest energy" does make sense, being the 0th component of the 
> 4-momentum and therefore having different values in different inertial frames.  
> All of this is 
> within the context of Special Relativity.

   True. But time between 2 distinct events in a moving system also is the 0th 
component of the 4-displacement between these events and therefore has different 
values in different inertial frames. And yet some physicists promote the term 
"proper time" as the only legitimate characteristic of time. This is against the 
very spirit of Special Relativity. 

Moses Fayngold,
NJIT