Question

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

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

Answer 1

Answer: (A)

$600W$

Answer 2

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

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