Momentum & collisions worksheet with answers

A 5 kg rifle, free to move, fires a 4 g bullet at 300 m/s. Both start at rest. Find the recoil speed V of the rifle.

A 500 kg car moving at 6 m/s collides head-on with a 1500 kg car moving at 5 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).

An 18 kg projectile moving horizontally at 36 m/s explodes into two fragments that move along the same line. The 7 kg fragment continues forwards at 81 m/s. Find the velocity v′₂ of the 11 kg fragment (positive in the original direction).

A 1000 kg car moving at 17 m/s runs into a stationary 1900 kg car and the two lock together. How much kinetic energy ΔK is lost in the collision?

A 5 g bullet is fired horizontally into a 2.5 kg block hanging from light strings 0.7 m long, and stays in it. The strings swing out to a largest angle of 30° from the vertical. Use g = 9.81 m/s². Find the speed v of the bullet before impact.

A 0.3 kg ball hits a wall at 16 m/s and bounces straight back at 11 m/s. The contact lasts 40 ms. Find the magnitude of the impulse J the wall gives the ball.