A QUANTITATIVE MAGNETIC BRAKING EXPERIMENT

A popular demonstration which often accompanies the introduction of ma gnetic induction is that in which a strong button-shaped magnet is dro pped through a long copper or aluminum tube. The induced currents caus e a retarding force which dramatically slows the descent of the fallin g magnet. Here, we describe methods of calculating and measuring the t erminal velocity and magnetic forces in the magnetic braking experimen t. The techniques are quite accurate, inexpensive to perform. and are suitable for introductory courses in electricity and magnetism.