Question

A bullet is fired with a speed of $1000m/\sec$ in order to hit a target 100 m away. If $g = 10m/s^{2}$, the gun should be aimed

• A. Directly towards the target
• B. 5 cm above the target
• C. 10 cm above the target
• D. 15 cm above the target

Answer 1

Answer: (B)

5 cm above the target

Answer 2

Bullet will take $\frac{100}{1000} = 0.1$sec to reach target.

During this period vertical distance (downward) travelled by the bullet $= \frac{1}{2}gt^{2}$ $= \frac{1}{2} \times 10 \times (0.1)^{2}m = 5\mspace{6mu} cm$

So the gun should be aimed 5 cm above the target.