Question

A gun of mass 3 kg fires a bullet of mass 30 g. The bullet takes 0.003 seconds to move through the barrel of the gun, and acquires a velocity of 100 m/s. Calculate:
a) the velocity at which the gun recoils
b) the force exerted on the gunman due to recoil of the gun.
I want the solution as well as the answer.

Answer 1

let m=0.03 kg be mass of bullet and it final velocity be vb
  M=3 kg be mass of gun and it's final velocity is vg
gun and bullets intial velocities are zero
well by conservation of momentum
M(vg)=m(vb)
3(vg)=(0.03)(100)
vg=1 m s-1
so this the velocity with which gun recoils