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Q.
A gun of mass 10 kg fires 4 bullets per second. The mass of each bullet is 20 g and the velocity of the bullet when it leaves the gun is 300 ms-1. The force required to hold the gun when firing is
Momentum of one bullet, p = mv
= 20 × 10$^{-3}$ × 300 = 6 kg m s$^{-1}$
N = number of bullet per sec = 4
$∴ \frac{dp}{dt}=$ change of momentum per sec or force
$\quad$$\quad$$\quad$= N(p - 0) = 4 × 6 = 24 N