Question

A machine gun fires a bullet of mass $40g$ with a velocity of $1200{ms}^{-1}$. The man holding it can exert a maximum force of $144N$ on the gun. How many bullets can he fire per second at the most?

• A. 1
• B. 3
• C. 2
• D. 4

Answer 1

The correct option is B 3

The man can exert a maximum force of $144N$ implies that this is the force that he can bear from the gun while the bullets are being fired.
So the maximum force from the gun can be $144$ N per sec.
$\therefore F=\frac{nmv}{t}$
$144=\frac{n\times 0.04\times 1200}{1}$
$\Rightarrow n=\frac{12}{4}=3$