Question

From an automatic gun a man fires 360 bullets per minute with a speed of 360 km/hr. If each bullet weighs 20g, the power of the gun is

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

Answer 1

The correct option is A 600 W

Power of gun = $\frac{\text{Total K.E. of fired bullet}}{\text{time}}$

Total KInetic Energy $=n\times \frac{1}{2}m{v}^2$

$P=\frac{n\times \frac{1}{2}m{v}^2}{t}=\frac{360}{60}\times \frac{1}{2}\times 2\times {10}^{-2}\times (100{)}^2=600W$