Grade 9 Physics Help

Question

A 10 kilogram shell is fired from a 500 kg gun with a velocity of 1000 m/sec. What is the recoil velocity of the gun?

Answer 1

Momentum is conserved meaning the momentum before the gun is fired must equal the momentum after the gun is fired.

Before the gun is fired the momentum is zero. After the gun is fired the momentum must also add to zero.

The momentum of the shell is mv = (10)(1000) = 10,000 kg•m/s

The momentum of the gun is mv = (500)(v)

So 10,000 + 500v = 0

Solve for v (you will get a negative result which just means the velocity is in the opposite direction from the velocity of the shell)