On a gently sloping golf green, the ball usually rolls to a stop regardless of whether it rolls up or down or across the slope. A simple experiment is described to show how the slope and the coefficient of rolling friction can be measured.

A common exercise in elementary mechanics is to calculate or measure the acceleration of a ball rolling down an inclined plane, assuming that the coefficient of rolling friction is negligible. That assumption is valid when a hard ball rolls down a hard surface but not when a soft ball rolls on a hard surface or when either a hard or a soft ball rolls on a soft surface. The latter situation is involved when a ball rolls on grass, as it does on a putting green, and then the ball usually decelerates rather than accelerates when it rolls down a sloping section of the green. The...

Supplementary Material

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