Re: correct answer

[Bob Sciamanda <sciamanda@worldnet.att.net>]

Dewey Dykstra, Jr. wrote:
> This, I believe, is the type of problem which first motivated Bruce
> Sherwood to realize that the standard form of the W-E Theorem presented in
> the C.M. frame does not work in this setting.  The object is deformable.
> . . .
> Dewey
It certainly DOES work!  The problem is the common erroneous tendency to 
expect the WE theorem to play the role of the conservation of energy - 
it makes no pretense to do so.  And yet it still works!  It knows only
about 
that work which results in changes of CM kinetic energy; it knows
nothing 
about other forms of energy.  Its remarkable usefulness is that one can
make 
such a statement about delta KE without regard to other (internal)
energy 
transformations.  In the present problem, whether or not the model used 
includes internal dissipation is irrelevant to the truth of the 
CM WE statement.

To lose the conceptual and calculational worth of the WE theorem by
hiding 
it inside a conservation of energy statement (and denying its separate 
existence and worth) is simply making an important aspect of Mechanics
only 
a part of thermodynamics.

-- 
Bob Sciamanda				sciamanda@edinboro.edu
Dept of Physics				sciamanda@worldnet.att.net
Edinboro Univ of PA			http://www.edinboro.edu/~sciamanda/home.html
Edinboro, PA				(814)838-7185