Question

Two objects A and B have masses in the ratio of 2 : 1 and are dropped from the same height.

1. What is the ratio of their velocities on reaching ground?
2. What is the ratio of their kinetic energy on reaching ground?

Answer 1

Assuming air resistance is negligible.

i. For an object dropped from rest through height h, v² = 2gh.

The final velocity does not depend on mass, so the ratio of their velocities is 1 : 1.

ii. Since K = `1/2 mv^2` and both objects have the same final velocity, their kinetic energies are in the ratio of their masses.

Therefore, the ratio is 2 : 1.