Momentum & collisions worksheet with answers

A 4.5 kg rifle, free to move, fires a 10 g bullet at 250 m/s. Both start at rest. Find the recoil speed V of the rifle.

A 1900 kg car moving at 8 m/s collides head-on with a 900 kg car moving at 7 m/s in the opposite direction. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).

A 10 g bullet is fired horizontally into a 2 kg wooden block hanging on light strings, and stays inside it. The block swings up until it is 13 cm higher than at the start. Use g = 9.81 m/s². Find the speed v of the bullet before impact.

A 12 kg projectile moving horizontally at 8 m/s explodes into two fragments that move along the same line. The 9 kg fragment continues forwards at 40 m/s. Find the velocity v′₂ of the 3 kg fragment (positive in the original direction).

A 0.15 kg ball hits a wall at 14 m/s and bounces straight back at 6 m/s. The contact lasts 25 ms. Find the average force F_avg of the wall on the ball.

At a crossing a 2000 kg car travelling east at 22 m/s collides with a 1100 kg car travelling north at 24 m/s. The cars lock together. Find the speed v′ of the wreck just after the collision.