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Re: [Phys-l] teaching energy



I just made a quick (5 minute) cursory glance at the reference below; it
appears very interesting, however, I'm bothered a bit by the discussion
of gravitational PE on page 3.

|
| Please read "Making Work Work" at
| <http://modeling.asu.edu/modeling/MakingWorkWork.pdf
<http://modeling.asu.edu/modeling/MakingWorkWork.pdf> >
|

The author makes much of saying saying that we won't say there is a PE
associated with the system of two masses, since we can't locate the
energy in either body. Therefore they conclude that it resides in the
gravitational field.

I fail to see what is wrong with associating PE with the system, the
distance between the objects being the state variable. They mention this
interpretation and then reject it.

I suppose they must do the same thing when it comes to discussing PE of
a system of 2 charges. I.e. the modelers calculate energy in a charge
configuration by integrating E^2 over a volume, rather than by
qQ/distance???

I have to go to class, now so I can't write more;

Any comments, discussion?

Joel R



________________________
Joel Rauber
Department of Physics - SDSU

Joel.Rauber@sdstate.edu
605-688-4293