[Phys-L] Re: work and heat

[Tom Wayburn <twayburn@WT.NET>]

=46rom: "Tom Wayburn" <twayburn@wt.net>
To: "Forum for Physics Educators" <PHYS-L@list1.ucc.nau.edu>
Subject: Re: work and heat
Date: Tuesday, January 31, 2006 5:44 PM

My answer to this question is the one I always give and some teachers=
 won't like it.  Heat and=20
work appear in the energy balance, but only heat appears in the entro=
py balance.=20
That's the difference.   I can't imagine discussing energy without a =
balance=20
equation.   Feynman talks about energy in terms of its conservation i=
n the story problem with blocks.   The entropy balance is simpler rea=
lly if you know what lost work,  L_cv, is.   It closes=20
the entropy balance for irreversible processes.

The equations I use are at http://dematerialism.net/baleqs31.htm .

Tom Wayburn, Houston, Texas

----- Original Message -----=20
=46rom: "Carl Mungan" <mungan@USNA.EDU>
To: <PHYS-L@LISTS.NAU.EDU>
Sent: Tuesday, January 31, 2006 3:48 PM
Subject: work and heat


> At the risk of opening a can of worms....
>
> In a short letter (see URL below), I ask the question why distingui=
sh
> work from heat in thermodynamic processes? I come up with two
> reasons, both of them fairly limited (to reversible processes and
> special kinds of irreversible processes only). (Conceivably one can
> come up with one more use, namely to help interpret certain terms
> that arise in statistical mechanics, but that's only useful for
> identification not calculation purposes.)
>
> I wonder if anyone can come up with any reasons I may have missed?
> Curious minds want to know. -Carl
>
> http://usna.edu/Users/physics/mungan/Publications/FEd2.html
>
> --
> Carl E. Mungan, Asst Prof of Physics  410-293-6680 (O) -3729 (F)
> Naval Academy Stop 9c, 572C Holloway Rd, Annapolis MD 21402-5002
> mailto:mungan@usna.edu     http://usna.edu/Users/physics/mungan/
> =20
_______________________________________________
Phys-L mailing list
Phys-L@electron.physics.buffalo.edu
https://www.physics.buffalo.edu/mailman/listinfo/phys-l