Re: TdS is not dQ or d(anything)

[Tim Folkerts <tfolkert@FHSU.EDU>]

> >      Let us test eq. /2/ by considering an analogous situation. We
> > have a large
> > group of people each of which possesses a certain amount of money. Let
> >
> > M = SUM n_i m_i                            /6/

Perhaps a better (but still imperfect) analogy is the net value of my
stocks.  I own (I wish!) n_i shares of company i at a value of m_i, so the
net value is
       M = SUM n_i m_i

My net value tomorrow depends on how many new shares I get:
      dM = SUM m_i dn_i
and how my stocks did:
      dM = SUM n_i dm_i

The restriction that the number of particles (shares) be constant is quite
artificial in this analogy (e.g. you always have to own exactly 10,000
total shares of stock).

If I follow Pentcho, then the first term would be analogous to dQ.  The
change in money is due to adding more high value stocks, and getting rid of
low value stocks. Of course, you can't do this without some inflow of
wealth.  The second term would be analogous to dW.  Someone did "work" on
the stocks to make them more valuable, in much the same way that doing work
on a cylinder decreases the volume and changes the "particle in a box"
energy levels.



Timothy Folkerts

Department of Physics
Fort Hays State University
Hays, KS  67601
785-628-4501

"The only thing necessary for the triumph of evil is for good men to do
nothing." - Edmund Burke