Re: TdS is not dQ or d(anything)

[Carl Mungan <mungan@USNA.EDU>]

Jim commented:

> It would be very
> nice if someone could give an example where the entropy of a system could
> be calculated due to any other mechanical macroscopic work where the
> entropy change is zero.

I'm not quite sure I know what you mean about calculating entropy
when its change is zero, but if you mean other mechanical macroscopic
processes in which delta(S) = 0, how about dropping a stone in
vacuum? a box which doesn't slip in the back of an accelerating
truck? any other nondissipative process (even ones involving
nonconservative forces)?

Furthermore, if we restrict ourselves to reversible processes between
equilibrium states, why do you object to dbar_Q = TdS? (I agree that
this restriction leaves out a lot of interesting physical situations
however.) Carl
--
Carl E. Mungan, Asst. Prof. of Physics  410-293-6680 (O) -3729 (F)
      U.S. Naval Academy, Stop 9C, Annapolis, MD 21402-5026
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