Question

A gun fire bullets each of mass $1 \, g$ with velocity of $10 \, m \, s^{- 1}$ by exerting a constant force of $5 \, g$ weight. Then, the number of bullets fired per second is (take $g=10 \, m \, s^{- 2}$ )

• A. $50$
• B. $5$
• C. $10$
• D. $25$

Answer 1

Answer: (B)

Mass of Each bullet, $\left(m\right)=1 \, g=0.001 \, kg.$
Velocity of bullet, $\left(v\right)=10 \, m \, s^{- 1}$
Applied force, $\left(F\right)=5$
$=\frac{5}{1000}\times 10=0.05 \, N.$
Let $n$ bullets are fired per second, then
Force = rate of change of linear momentum
i.e., $F=n\times mv$
$\therefore \, \, $ Number of bullets fired per second,
$n=\frac{F}{m v}=\frac{0.05}{0.001 \times 10}=5$