Question

A boy aims at a bird from a point at a horizontal distance of $100m$. The gun can impart a velocity of $500$ $m{s}^{-1}$ to the bullet. At what height above the bird must he aim his gun in order to hit $(g=10$ $m{s}^{-2}$) :

• A. $20cm$
• B. $40cm$
• C. $50cm$
• D. $100cm$

Answer 1

The correct option is A $20cm$

Time taken by bullet to cover horizontal Distance $=100/500=0.2sec.$
Distance covered by bullet in same time$=0\times t+\frac{1}{2}g{t}^2=0.5\times 10\times 0.2\times 02=0.2m=20cm$

Boy should aim 20cm above to hit the bird