A machine gun of mass 10 kg fires 20 g bullets with speed of 500 m/s at the rate of 10 bullets per second. To hold the gun steady in its position how much force is necessary?

Options

A. 200N
B. 500N
C. 100N
D. 250N

Answer

C

Explanation

Momentum of 10 bullets each of 20g
`=20/1000 times 500 times 10=100 kg m//s`
Applying law of conservation of momentum,
Momentum of gun=`-100 kg m//s`
Required force= `("Chang e I n momentum of gun")/("Time")`
`=(100-0)/1=100N`