Question

A machine gun fires 360 bullets per minute. Each bullet has a mass of 5 grams and travels at 600 m/s. What is the power of the gun? (Assume no loss of energy and 100% power transmission)

(a) 300 W

(b) 600 W

(c) 900 W

(d) 1800 W

This question was posed to me in semester exam.

My question comes from Power in chapter Work, Energy and Power of Physics – Class 11

Answer 1

Right choice is (c) 900 W

Explanation: No. of bullets fired per second = 360/60 = 6

Power of the gun is completely transmitted to bullets.

Power (P) = Power of bullets in 1 second

 = [(1/2 x m x v^2) x 6] / 1

m = 5 x 10^-3 kg

v = 600 m/s

P = (1/2 x 5 x 10^-3 x 600^2 x 6) / 1

 = 900 W.