Question

A bullet of mass 20 kg is fired horizontally with the velocity' of 150 m|sec from ofa pistole of mass 2 kg find the recoil velocity of the pistol

Answer 1

mass of bullet=20g=0.02
velocity of bullet=150ms
mass of gun = 2 kg
velocity of gun=V

momentum before rest= (0.02*2)*0
                                    =0 ms

momentum after fire=(0.02*150)(2+V)
                                =3+2V
According to law of conservation of momentum
momemtum before rest=momentum after firing
                                    0=3+2V
                                     V=-3/2
                                        =-1.5 m/s