The expanding gases that leave the muzzle of a rifle also contribute to the recoil. A .30 caliber bullet has mass 7.20×10?3kg and a speed of 601m/s relative to the muzzle when fired from a rifle that has mass 2.80kg . The loosely held rifle recoils at a speed of 2.05m/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.