Question

A machine gun fires 200 bullets per minute with a velocity of 60 m/s. What is the power of the machine gun if the mass of each bullet is 0.05g?

Answer 1

We know that, kinetic energy =$\frac{1}{2}m{v}^2$
So total energy imparted to 200 bullets, $E=\frac{1}{2}\times 200\times \left(\frac{0.05}{1000}\right)\times 60\times 60=18J$
So, power =$\frac{Energy}{Time}=\frac{18}{60}J/s=0.3W$