Question

A bullet is to be fired with a speed of 2000 $m{s}^{-1}$ to hit a target 200 m away on a level ground. If g = 10 $m{s}^2$, 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

Answer 1

The correct option is C 5 cm above the target

Let t be the time taken by bullet to hit the target. Let h be
the height of gum above the target.
$\therefore 200m=\left(2000m{s}^{-1}\right)\times t\left(s\right)ort=\frac{200}{2000}=\frac{1}{10}sNow,h=\frac{1}{2}g{t}^2=\frac{1}{2}\times 10\times {\left(\frac{1}{10}\right)}^2=\frac{1}{20}m=5cm$