A shell of mass 0.020 kg is fired by a gun of mass 100 kg. If the muzzle speed of the shell is 80 m/

Question

A shell of mass 0.020 kg is fired by a gun of mass 100 kg. If the muzzle speed of the shell is 80 m/s, what is the recoil speed of the gun?

Professor PC Thomas Classes · Answer

By conservation of momentum: $m_{	ext{gun}} v_{	ext{gun}} = m_{	ext{shell}} v_{	ext{shell}} \implies 100 	imes v = 0.020 	imes 80 = 1.6$. So $v = \frac{1.6}{100} = 0.016$ m/s.