Re: dW turns into dQ

[Joel Rauber <Joel_Rauber@SDSTATE.EDU>]

Bob wrote:

> This might be compared to asking, in F=mA, "if F includes the sum of
> electrical, gravitational, etc forces and only their (vector)
> sum matters
> for calculating A, why the partitioning?"  Of course it is
> because this
> partitioning is our way of enabling the calculation of that
> sum, but the
> resulting A wouldn't care if you used a different
> partitioning (taxonomy
> of F) so long as you applied the same vector sum.
>
> Bob

I wonder???? I realize that in your above analogy, it is only an analogy;
but I have a gut feeling that it is different.  The partitioning in the NII
example above, is in essence a coordinate system choice.  And the physics
doesn't care what coordinates you choose to describe the process with.

In thermodynamics . . .  my gut tells me the physics probably does care
whether something is dQ or dW (of course that gut feeling may simply be the
brownie I just ate). . . Namely we also have the 2nd law (of thermodynamics)
to worry about . . . but to what degree?

I don't think such a big deal would be made out the distinction if something
so analgous were the case. (and hence such a long phys-L discussion)

Joel


> Bob Sciamanda (W3NLV)
> Physics, Edinboro Univ of PA (em)
> trebor@velocity.net
> http://www.velocity.net/~trebor
>
>
>
> > . . .
> > If the partitioning is totally arbitrary once a specific process and
> > time-scale is determined, why bother partitioning at all?
> > . . .
> > Joel