Q. A bullet is to be fired with a speed of $2000\ ms^{- 1}$ to hit a target $200\ m$ away on a level ground. If $g = 10\ ms^{- 2}$, the gun should be aimed
A) Directly at the target
B) $5\ cm$ below the target
C) $5\ cm$ above the target
D) $2\ cm$ above the target
Explanation
(c) Let $t$ be time taken by the bullet to hit the target
$\therefore 200\ m = 2000\ ms^{- 1}t$
$\Rightarrow t = \frac{200m}{2000ms^{- 1}} = \frac{1}{10}s$
For vertical motion,
Here $u = 0$
$\therefore h = \frac{1}{2}gt^{2}$
$h = \frac{1}{2} \times 10 \times \left( \frac{1}{10} \right)^{2} = \frac{1}{20}m = 5\ cm$
$\therefore$ Gun should be aimed $5\ cm$ above the target
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.