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Re: a relativity question

All definitions are, by definition, arbitrary. While you may have
good reasons, according to your definition of "good", for your choice of
definitions, others may find it convenient to make other choices.
Regards,
Jack
"What's in a name?..."

On Tue, 26 Nov 2002, John Mallinckrodt wrote:

Jack Uretsky wrote:

Be not so arbitrary, John. It is a matter of convention as to whether
"mass" means restmass or it means the energy of a system divided by c^2.
Using the latter definition, and delta E = mgh, one gets the correct
answer for the Pound-Rebka experiment and 1/2 the correct answer for the
bending of light by the sun (the other half we can ascribe to the
curvature of space).

Convention is like religion, you know. Whatever gives you your jollies is
fine with me.

Fair enough, I guess.

However, I don't think I'm the one who is being "arbitrary." It
seems to me that there is remarkable clarity to be had by subscribing
to the increasingly accepted (and *not* at all arbitrary) convention
that "mass" means "invariant mass." Indeed, I think the question
that initiated this thread is a very direct and obvious result of the
confusion engendered by teaching that mass is simply "energy (of any
kind) divided by c^2."

--
John Mallinckrodt mailto:ajm@csupomona.edu
Cal Poly Pomona http://www.csupomona.edu/~ajm

This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.


--
"What did Barrow's lectures contain? Bourbaki writes with some
scorn that in his book in a hundred pages of the text there are about 180
drawings. (Concerning Bourbaki's books it can be said that in a thousand
pages there is not one drawing, and it is not at all clear which is
worse.)"
V. I. Arnol'd in
Huygens & Barrow, Newton & Hooke

This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.