Re: CONSERVATION OF ENERGY

[brian whatcott <inet@intellisys.net>]

I am pleased to see another respectable input on this topic.
It is interesting that the academic contributors positively writhe in
discomfort on the work/heat details.

 Al for example holds out that negative work is done on the block
and zero work is done on the slide, while it is in fact obvious to him and
everyone else that SOME work is expended on both: if only from the
minuscule scratches which always occur to the surfaces in contact in this
situation.
Regards
brian

At 15:48 7/18/97 -0400, Al Clark wrote:
> On Tue, 15 Jul 1997, brian whatcott wrote:
>
> > Assume both pieces stabilize at same temp., and radiative heat loss is
> > sensibly constant.
> >
> > > 3) How much heat is generated? How much work is done? Explain what happens
> > >   to the initial kinetic energy of the iron cube.
> >
> > Heat - 50 joules
> > Work 0 joules
> > The initial KE is modeled as all converted to heat.
> >
> > > *********************************************************************
>
> I disagree.
> No heat is generated; heating is a process. The internal energy increases 
> by 50 J.
> Work done on block = -50 J.
> No work done on plate in this idealization.
> KE is converted into internal energy.
>
> However, I hope the writers would be more careful in stating the problem.
>
> Al Clark
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brian whatcott <inet@intellisys.net>
Altus OK