Re: is the magnetic field really moving?

On Sat, 2 Aug 2008 03:17:52 -0700 (PDT) Benj <bjacoby@[EMAIL PROTECTED]
> wrote:
| On Aug 1, 8:42?pm, phil-news-nos...@[EMAIL PROTECTED]
 wrote:
| 
|> If I place a round magnet near a round piece of iron, where each are on
|> separate axles aligned in the same axis and free to rotate, would
rotating
|> the magnet cause the iron to rotate?
| 
| This experiment has been done and the answer is "no" [even if the Iron
| is another magnet].
| 
| This answer should be obvious if you take a bit of time to examine the
| forces generated by the fields on the pieces. Even if you assume the
| field of the rotating magnet is rotating with it, you find that there
| is NO mechanism that can impart rotational forces to the second piece.
| All forces that might be generated are in the wrong directions.

Now the next question (before I extend this on to the Faraday Homopolar
Generator) is, would a non-rotating magnet cause a non-rotating round
piece
of iron to slow down and stop?  Your description would suggest "no" even
in
this case.  That would then suggest that motion of a wire _in_ (but not
across) a magnetic field (e.g. the magnet is moving with the wire) could
generate an electrical potential.

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