Re: [Phys-L] irreversible quasistatic

["Daniel V. Schroeder" <dschroeder@weber.edu>]

Carl, I can't speak for all authors, but your example is exactly the type of situation that *I* would call irreversible and quasistatic.  More generally, the two objects are weakly coupled in the sense that their internal relaxation times are short compared to the relaxation time for them to come to equilibrium with each other--and therefore we can consider each object to be internally in equilbrium at all times.

Cheers,

Dan


> From: Carl Mungan <mungan@usna.edu>
> Subject: [Phys-L] irreversible quasistatic
> Date: July 28, 2016 2:48:25 PM MDT
> To: PHYS-L <phys-l@phys-l.org>
>
>
> I'm often uncertain about the idea of irreversible quasistatic processes,
> mostly because thermo textbooks don't give many examples.
>
> Would the following process be an example of such a process? Explain why
> not if you don't think so.
>
> One hot plate at temperature T_H is parallel to a cold plate at T_C. The
> plates are oriented vertically with a small pendulum ball suspended between
> them. The ball is set swinging, so that it hits the plates at the end of
> its motion back and forth. The ball carries small increments of thermal
> energy dE from the hot plate to the cold plate. The time t when the ball is
> swinging through free space between the two plates allows the two plates to
> re-equilibrate internally. In this way each plate is ever only
> infinitesimally out of thermal equilibrium, yet I am accomplishing a net
> energy transfer from the hot to the cold plate.