Philip raises a lot of good points, but this question has been answered.
The main work was done back in the 50's and 60's. I did my term paper
for my undergraduate thermo class on relativistic thermodynamics. I can
try to look it up at home if anyone wishes and I can then also supply
references.
Unfortunately, I wrote it on a Mac and will have find acces to one to
try to send electronic copies if people wish. Let me know what info
people want.
Sam Held
-----Original Message-----
From: Philip Zell [mailto:Zell@ACT.ORG]
Sent: Wednesday, February 17, 1999 12:30 PM
To: PHYS-L@LISTS.NAU.EDU
Subject: Re: A question on inelastic relativistic collisions
\Ed Schweber (edschweb@ix.netcom.com)
\Physics Teacher at The Solomon Schechter Day School, West Orange, NJ
\To obtain free resources for creative physics teachers visit:
\http://www.physicsweb.com
\Hi gang:
\The problem with the week long February break many schools have,
besides
\that it wastes class time, is that it gives us teachers too much time
to
\think.
\Anyway, I was wondering: Since in special relativity, momentum and
energy
\are merged into a single four vector whose components will be different
\for different moving observers, does that mean that the amount of heat
\lost in an inelastic collision is relative to the observer?
\If so, what does that do to specific heats and latent heats. Do
these
\also become relativistic quantities?
\What about Kelvin temperature. Is that absolute or relativistic?
Kelvin
\temperature is proportional to the average KE per molecule and would
not
\that average KE be relative to the motion of the observer?
\Thanks in advance for any input and I promise in the future that I
will
\stop trying to think.
\Ed Schweber
I like this question, because it opens so many avenues for
discussion.
Some thoughts and questions, not well organized, to provoke further
discussion. I apologize in advance for any ambiguity and outright
errors I introduce into the discussion. I just want to join in the
fun.
1. Heat is a macroscopic phenomenon that helps describes the
average
behavior of large ensembles of particles. In a single collision,
we
deal with energy and momentum.
2. Temperature, specific heat, and latent heat are also macroscopic
properties used to describe a system of particles.
3. Temperature has different interpretations. For example it can
refer to the maxwellian that describes the speed distribution of
the
ensemble of particles in thermal equilibrium. It can refer to the
degree of excitation of bound electrons in an ensemble of atoms, as
described in a second distribution function. It can refer to the
degree of ionization of an ensemble of atoms, as described in a
third
distribution function.
4. What does a distribution function, determined for a system of
particles in the frame of a stationary lab, look like when some of
the
particles in the system are moving relativistically with respect to
the lab frame, but the center of mass of the distribution is not
moving relativistically (ie, meltdown)? How, if at all, are the
expressions for heat capacity and latent heat of the system of
particles affected?
5. How are the expressions for latent heat and heat capacity of a
system of particles affected if the center of mass of the system of
particles is moving relativistically with respect to the lab frame
and
the expressions are determined by an observer in the lab frame?