Q. The velocity of a bullet is reduced from $200\ m/s$ to $100\ m/s$ while travelling through a wooden block of thickness $10\ cm$. The retardation, assuming it to be uniform, will be
A) $10 \times 10^{4}\ m/s^{2}$
B) $12 \times 10^{4}\ m/s^{2}$
C) $13.5 \times 10^{4}\ m/s^{2}$
D) $15 \times 10^{4}\ m/s^{2}$
Explanation
(d) $u = 200\ m/s,\ v = 100\ m/s,s = 0.1\ m$
$a = \frac{u^{2} - v^{2}}{2s} = \frac{(200)^{2} - (100)^{2}}{2 \times 0.1} = 15 \times 10^{4}\ m/s^{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.