Moment of inertia: Hoop or disk rotated by falling weight.

Moment of Inertia Apparatus. The apparatus consists of a light weight aluminum cross rotating in a horizontal plane about a vertical axis. The cross serves as a carrier for a pair of objects whose moment of inertia is to be determined. The axle of the apparatus is driven by means of a string drawn from a drum passing over a pulley and loaded with a weight. Set up so that when string is completely extended, weight does not touch the floor. Starting position has weight near top pulley.