A rifle rests on a frictionless horizontal surface
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A 3.0kg rifle rests on a frictionless horizontal surface. The rifle is initially at rest. When the trigger is pulled, it fires a single 0.010kg bullet that emerges from the muzzle at 400ms−1 measured relative to the ground.
(a) Calculate the recoil speed of the rifle immediately after the bullet leaves the barrel.
(b) Determine the ratio of the bullet’s kinetic energy to the rifle’s kinetic energy just after the shot is fired.
(c) Briefly explain, in words, why the lighter object acquires much more kinetic energy than the heavier object even though the magnitudes of their momenta are equal.