PURPOSE: Application of conservation of energy in a rolling object.

DESCRIPTION: Q: Which is faster, rolling or sliding? An aluminum cylinder rolls down the incline. An identical cylinder has tiny ball bearings on one end so that it slides without friction down the incline. If the two cylinders are started from the top at the same time, which will reach the bottom first, rolling, sliding, or a tie? A: sliding is faster. Click your mouse on the photograph above to view an mpeg video of the action.

SUGGESTIONS: Let your students guess what will happen before performing the experiment.

See Question of the Week #11 for information on using this demonstration to enhance class involvement.

REFERENCES: (PIRA unknown.)

EQUIPMENT: Rolling and sliding cylinders, inclined plane.

SETUP TIME: None.