Explanation

(d) Work done by the gun
=Total kinetic energy of the bullets
$= n = \frac{1}{2}mv^{2}$
$= 240 \times \frac{1}{2} \times 10 \times 10^{- 3}(600)^{2}$
$= 120 \times \frac{1}{2} \times 10 \times 10^{- 3} \times 600 \times 600$
$\therefore\ \ \ \ \ \ Power\ of\ gun = \frac{work\ done}{time\ taken}$
$= \frac{120 \times 10 \times 10^{- 3} \times 600 \times 600}{1min}$
$= \frac{120 \times 10 \times 360}{60} = 120 \times 10 \times 6w$
$\frac{120 \times 10 \times 6}{1000}kW = 7.2kW$