go figger
Charles Spitzer wrote:
....
a neat trick: suspend a large horseshoe magnet on a string centered over an
Al plate that is on a low friction turntable. rotating the magnet will cause
the Al plate to rotate.
Ah - that's the phenomenon used in mechanical speedometers. A magnet
rotated by the cable, an aluminum disk fastened to the needle, &
restrained by a spring.
Bob
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