Question

State the principle of conservation of momentum. Using this, find the expression of recoil velocity of a gun.

Answer 1

Hey mate,

◆ Principle of conservation of momentum-
- It states that the momentum of a system is constant if there are no external forces acting on the system.
- Simply, initial momentum before collision is equal to final momentum after collision.

◆ Recoil velocity of gun-
Here, initially both gun and bullet are at rest so
Initial momentum = 0

Now, let a bullet of mass m fired through a gun of mass M with velocity v amd v' is recoil velocity if gun.
Final momentum = mv + Mv'

From law of conservation of momentum,
Initial momentum = Final momentum
0 = mv + Mv'
v' = -mv/M

Recoil velocity of gun will be -mv/M.

Hope that is useful...