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- From: palmer@sfu.ca (Leigh Palmer)
- Subject: Re: Converting the masses
- Message-ID: <1992Jul27.191259.5549@sfu.ca>
- Sender: news@sfu.ca
- Organization: Simon Fraser University
- References: <n0596t@ofa123.fidonet.org> <mcirvin.711489157@husc10> <9868@sun13.scri.fsu.edu> <1992Jul22.193837.18095@sfu.ca> <mcirvin.711904014@husc8>
- Date: Mon, 27 Jul 1992 19:12:59 GMT
- Lines: 27
-
- In article <mcirvin.711904014@husc8> mcirvin@husc8.harvard.edu (Mcirvin)
- writes:
- >palmer@sfu.ca (Leigh Palmer) writes:
- >
- >> "Mass" as you use it
- >>is equal to neither inertial nor gravitational mass as those terms apply to
- >>any system more complicated than a particle at rest!
- >
- >Which only illustrates that those concepts are only really useful in
- >the context of Newtonian physics, IMHO.
- >
- >To further confuse the
- >>beginning physics student you could explain that the mass of that lump of
- >>matter is independent of its temperature.
- >
- >Actually, neither definition of mass would be temperature-independent,
- >if you define it for the whole lump of coal. When you raise the
- >temperature, the energy in the rest frame increases! The sum of
- >the masses of all the particles is perhaps temperature-independent,
- >but as you complained before, that's not the mass of the lump.
-
- Exactly my point. The existence of an internal degree of freedom in a lump
- of coal which affects its mass vitiates the particle physicists' definition.
- Used outside particle physics this convention has no conspicuous advantages,
- and indeed it may lead to conceptual problems of its own.
-
- Leigh Palmer
-