Question

A gun of mass 5 kg fires a bullet of mass 0.02 kg . the bullet leaves the barrel of the rifle at a velocity 120 m /s . if the bullet takes 0.1 s to travel through the length of the barrel, calculate the force experienced by the rifle due to its recoil.

Answer 1

Mass of gun =5kg
Mass of bullet =0.02
Velocity of bullet =120m/s
Time =0.1
Recoil velocity of gun =?
Mass of bullet ×velocity of bullet =mass of gun × recoil velocity of gun
0.02 ×120=5×required velocity of gun
Recoil velocity of gun =0.02 ×120/5
0.48 m/s
Momentom of bullet =mass of bullet ×velocity of bullet
0.02 ×120
2.4 kg. m/s
now suppose the required velocity of gun is V
m/s
momentum of gun =mass of gun ×required velocity of gun
5×Vkg. m/s
according to the law of conservation of momentum :
momentum of bullet =momentom of gun
2.4 =5×V
V= 2.4 ×5
0.48m/s
recoil velocity of gun V=0.48m/s