Question

Bullets of mass $40g$ each are fired from a machine gun with a velocity of ${10}^{3}m/s$. If the person firing the bullets experience an average force of $200N$, then the number of bullets fired per minute will be:

• A. $300$
• B. $600$
• C. $150$
• D. $75$

Answer 1

The correct option is A $300$

$\text{Step 1: Newton's Second Law}$

$\Rightarrow F=\frac{\Delta p}{\Delta t}=\frac{m\Delta v}{\Delta t}\times n$ [$n$ is the number of bullets per minute]

$\Rightarrow 200N=n\times 0.04\left(kg\right)\times \left(\frac{{10}^3\left(m/s\right)-0}{60\left(s\right)}\right)$

$\Rightarrow n=300$

Hence the correct option is $A$.