Re: Correct Answer

[John Mallinckrodt <ajmallinckro@CSUPomona.Edu>]

On Wed, 15 Oct 1997, Clarence Bennett wrote:

> How can the string stay vertical?
> If the bar turns, it should stay centered under the top of the string,
> unless it is pulled to the side.
> But a uniform field would not pull it.

If the field is uniform, only two forces act on the magnet--gravity and
string tension.  Thus, the string must remain vertical.  However, the two
forces must go "noncolinear" to become a couple and counter the magnetic
torque.

This has always been one of my favorite conceptual problems too.  It's a
shame it has been pulled from the new edition of H&R&K.

John
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