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Re: [Phys-l] non-conservative --> non-grady ???



John D. wrote in part:

|
| Well, I've been claiming all along that there isn't a
| profound difference. A force is a force. The particle being
| accelerated doesn't much care whether the force is grady or
| non-grady. In particular, the work/KE theorems don't care
| whether the force is grady or non-grady.
|
| Most importantly, our notion of conservation of energy
| doesn't distinguish between grady and non-grady forces. Both
| are required to uphold conservation of energy, no exceptions.
|

I think that this is an important point. The particle doesn't care
whether the force was conservative or not.

An analogous and often confused situation occurs when observing a charge
accelerated by an electric field. The charge doesn't care whether the
electric field was "grady" or "non-grady" (sorry John, I just have to
put quotes around grady). I.e. whether is was a conservative electric
field or a non-conservative electric field (in one version of the usual
language).

Recognizing that distinction doesn't matter as far as the electron goes,
helps a lot in trying to untangle what forces are doing mechanical work
on charges in EMF situations; particularly for motional emf, since we
know that magnetic forces can not be doing the mechanical work in moving
the charges around the circuit loop.