Question

A hockey ball of mass 200 g travelling at 10 m s⁻¹ is struck by a hockey stick so as to return it along its original path with a velocity at 5 m s⁻¹. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.

Answer 1

Mass of the hockey ball, m = 200 g = 0.2 kg

Hockey ball travels with velocity, v₁ = 10 m/s

Initial momentum = mv₁

Hockey ball travels in the opposite direction with velocity, v₂ = −5 m/s

Final momentum = mv₂

Change in momentum = mv₁ − mv₂ = 0.2 [10 − (−5)] = 0.2 (15) = 3 kg m s⁻¹

Hence, the change in momentum of the hockey ball is 3 kg m s⁻¹_.