Question

A 1 g object traveling at 10 m/s collides with a stationary 100 g object at rest and bounces back at the same speed. Assuming conservation of momentum, what is the speed of the 100 g object after the collision?​

Answer 1

m vi = initial momentum

m vf + M V = final momentum

M V = m (vi - vf) combining equations

V = m / M (vi - vf)

Let vf = 10 m/s and vi = -10 m/s

Then V = 1/100 * (-20 m/s) = -.2 m/s