Question

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

• A. $One$
• B. $Four$
• C. $Two$
• D. $Three$

Answer 1

Answer: (D)

$Three$

Let $n$ be the maximum no. of bullets fired by man per sec.
$\therefore$ Force $=$ rate of change of momentum

$F=nm\Delta V$
$144=n\times \frac{40}{1000}\times 1200$
$\Rightarrow n=3$