Q. A bullet of mass 0.05 kg moving with a speed of $80\ {ms}^{- 1}$ enters a wooden block and is stopped after a distance of 0.40 m. The average resistive force exerted by the block on the bullet is
A) 300 N
B) 20 N
C) 400 N
D) 40 N
Explanation
(c) $Resistive\ force = \frac{initial\ kinetic\ energy}{stopping\ distance}$
$= \frac{\frac{1}{2} \times 0.05 \times {(80)}^{2}}{0.40} = 400N$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.