Mass of bullet =m=100g=100 /1000kg=1/10kg
Velocity of bullet, v=100ms-1
Mass of gun, M=20kg
We have to determine the velocity of recoil of the gun
Let us assume the recoil velocity of the guns as V
The system (gun+bullet) is at rest, therefore, initial momentum of the system =0
Final momentum of the system = momentum of bullet + momentum of gun
mv+MV = 1/10 X 100 + 20 V= 10 +20 V
On applying law of conservation of momentum,
Final momentum = Initial momentum
V=− 10/20 = 0.5ms-1
Negative sign indicates that the direction of recoil velocity of the gun is opposite to the direction of the velocity of the bullet.
Articles to explore
1. What is momentum? Write its SI unit. Interpret force in terms of momentum. Represent the following graphically (a) momentum versus velocity when mass is fixed. (b) momentum versus mass when velocity is constant.