Question

A ring and a solid sphere roll down the same inclined plane without slipping. They start from rest. The radii of both bodies are identical and the ratio of their kinetic energies is $\frac{7}{x}$ where $x$ is \\_\\_\\_\\_\\_\\_\\_.

Answer 1

In pure rolling motion, the work done by friction is zero. Hence, the potential energy is completely converted into kinetic energy. Since the ring and the sphere initially have the same potential energy, they will also have the same total kinetic energy at the end.

- Ratio of kinetic energies = 1.

Given:

$\frac{7}{x} = 1 \implies x = 7.$

The Correct answer is: 7