Answer to Question #242908 in Physics for rshiii

Question

11. The expanding gases that leave the muzzle of a rifle also contribute to the recoil. A 30-caliber bullet has mass 0.00720 kg and a speed of 601 m/s relative to the muzzle when fired from a rifle that has mass 2.80 kg. The loosely held rifle recoils at a speed of 1.85 m/s relative to the earth. Find the momentum of the propellant gases in a coordinate system attached to the earth as they leave the muzzle of the rifle.

Answer 1

$$P=-mV+Mv\\P=-(0.0072)(601)+(2.8)(1.85)=0.85\frac{kgm}{s}$$