Re: [Phys-L] work versus mechanical transfer of energy

[Carl Mungan <mungan@usna.edu>]

> > Consider the equation
> >
> >         dE =  T dS   -   P dV                       [1a]
>
>
> that equation is only valid for  a path complete developed through
> equilibrium states and  in a reversible process

Why do you say that? This equation is basically a Taylor expansion of a function. As John Denker has already said, it’s just calculus. Reversibility does not enter into it *unless* you try to equate TdS with “heat” and -PdV with “work” which is a different ball of wax altogether.

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Carl E Mungan, Assoc Prof of Physics  410-293-6680 (O) -3729 (F)
Naval Academy Stop 9b, 572C Holloway Rd, Annapolis MD 21402-1363 
mailto:mungan@usna.edu     http://usna.edu/Users/physics/mungan/