Question

A gun fires $10$ bullets/sec each of mass $10\text{gm}$, with a muzzle velocity of $50\text{m/s}$. Find the force required to hold the gun in position.

• A. $5\text{N}$
• B. $10\text{N}$
• C. $15\text{N}$
• D. $20\text{N}$

Answer 1

The correct option is A $5\text{N}$

Number of bullets fired per second $=n=10$
Total change in momentum per second due to bullets $=\Delta p=nm(v-u)=10\times 10\times {10}^{-3}(50-0)=5\text{kg m/s}$
Force required to hold the gun in position $=\frac{\Delta p}{t}=\frac{5\text{kg m/s}}{1\text{s}}=5\text{N}$