Racing on a plane

HOW

1. You have an inclined plane and objects with the same mass but a different mass distribution.
2. Roll the objects to the “Start” position and release them freely at the same time.
3. Observe their movement.

WHY

When objects roll, their kinetic energy increases by as much as their potential energy decreases. This follows from the law of conservation of energy.

Kinetic energy, on the other hand, consists of the kinetic energy of translational motion and that of rotational motion. For an object with mass distributed further from the axis of rotation, the greater part of the kinetic energy is that associated with rotation and the lesser part is associated with translational motion. That is why this object rolls more slowly.

The observed effect is used by dancers when doing pirouettes. By bringing their arms together, they spin faster. You can carry out a similar experiment at the Small Merry-go-round station.