Re: Missing Energy

[Mark Sylvester <msylvest@SPIN.IT>]

At 18:03 20/05/99 -0400, Michael Edmiston wrote:
...
> In light of item (2), I do not understand Mark's (and others')
> viewpoint that it is interesting that the dissipated energy depends on
> the initial and final states rather than the "dissipation factor"
> involved.  Isn't that the way it always works?  The energy difference
> between two states is the energy "dissipated" regardless of how (or how
> fast) the energy is dissipated.  If a ball drops straight down from a
> certain height, or rolls down an incline (same height), or falls
> through a viscous medium (through same height), or ricochets down a
> maze of pegs (from same height), the energy lost is the same in all
> cases.  If that does not amaze us, the capacitor problem should not
> amaze us.

You're right of course - what makes the capacitor problem (or it's
mechanical analog) puzzling is the fact that approaching it from the usual
electrical circuit assumptions we neglect both R and L. For the example of
the falling mass, it's like assuming that it has gravitational mass, so can
change PE, but has negligible inertial mass, so does not gain KE, and
furthermore there's no friction!

Mark


Mark Sylvester
United World College of the Adriatic
34013 Duino TS
Italy.
msylvest@spin.it
tel: +39 040 3739 255