A rolling steel ball bearing of mass 27.5 g collides elastically with a small toy car of mass 52.0 g.If after the collision,the car moves at 1.25 m/s to the right,with what direction and speed was the ball bearing rolling prior to the collision?

Question

Quizplus · Accepted Answer

We can use conservation of momentum and energy to solve this problem. 
First, we find the initial velocity of the ball bearing by considering momentum conservation: 
m_ball * v_ball = (m_ball + m_car) * v_final 
where v_final is the final velocity of the car after the collision. 
Plugging in the given values, we get: 
v_ball = (m_ball + m_car) * v_final / m_ball = (27.5 + 52) * 1.25 / 27.5 = 1.81 m/s 
So the ball bearing was rolling to the right at 1.81 m/s before the collision.

A Rolling Steel Ball Bearing of Mass 27