Re: Swartz letter in AJP (work-energy theorem)

[Larry Smith <larry.smith@SNOW.EDU>]

At 10:26 PM -0600 8/31/04, Jim Green wrote:
> Then he attacks friction.  Let's take a side bar: consider a cold widget
> which is sliding on ice,  the widget slows.  therefore its level of energy
> is decreased.  The _only_ way to change the level of energy of a system is
> to do work on the system.  What then does this work?  Obviously it is the
> ice.  But how?  By exerting a frictional force.  Hence, friction does
> work.  And again he does not understand the work/energy theorem.

Definitions of words such as cavalier are very interesting, but the nub of
the discussion is Jim Green's paragraph above.  Of course there is negative
work, whenever the energy level of an object is decreased, and it isn't
beyond freshman to understand this.

Larry