This question is an extension of Question #217.
The device pictured below at the left consists of a strong (about 1 Tesla) cylindrical magnet, with its North pole extending out from its connection to a motor that rotates at 1725 revolutions per minute (28.75 revolutions per second) when the motor is turned on. The photograph at the right shows a detail of the magnet, in which you can see brushes of the type used to transmit current in a generator or motor commutator. One of the brushes touches the center of the cylinder at the North pole end, and one touches the magnet at its center or "equator," midway between the North and the South poles. The brush at the North pole end is connected to the positive terminal of a digital voltmeter, and the brush at the equator of the cylinder is connected to the negative terminal of the voltmeter.
When the motor is started, causing the magnet to rotate rapidly in the clockwise direction when viewed looking from the South end of the magnet back toward the motor:
Click here for Answer #218 after April 25, 2005.
