Use this item for studying the dependence of the moment of inertia on the distribution of mass. Roll a metal ring and wooden disk of the same mass and diameter on an inclined plane or a level surface. The moment of inertia is displayed! The product is comprised of a metal ring and a wooden disk of diameter 6″ (150 mm), 2″ (50 mm) thick and both the same mass. When these are rolled down on an inclined plane or on a level surface with the same initial impulse, the difference in acceleration can be studied.