Question

A plastic ball of mass 0.200 kg moves with a velocity of 0.30 m/s. This plastic ball collides with a second plastic ball of mass 0.100 kg that is moving along the same line at a velocity of 0.10 m/s. After the collision, the velocity of the 0.100 kg ball is 0.36 m/s. What is the velocity of the second ball?

Answer 1

Velocity of 0.2 kg ball is 0.17 m/s

Explanation:

Let the mass of balls be m and M.

Initial velocity ball 1 be u₁, ball 2 be u₂

Final velocity ball 1 be v₁, ball 2 be v₂

Initial momentum = m x u₁ + M x u₂ = 0.2 x 0.3 + 0.1 x 0.1 = 0.07 kgm/s

Final momentum = m x v₁ + M x v₂ = 0.2 x v₁ + 0.1 x 0.36 = 0.2v₁ + 0.036

We have momentum conservation

Initial momentum = Final momentum

0.07 = 0.2v₁ + 0.036

v₁ = 0.17 m/s

Velocity of 0.2 kg ball is 0.17 m/s