A rifle with a muzzle velcity of `100 ms^(-1)` shots a bullet at a small target 30 m away in the same horizontal line. How much height above the target must the rifle be aimed so that the bullet will hit the taget ?

Explanation

Let `theta` is the angle of projection of bullet .
Let the rifle be at O and traget at T.
As OT , is horiontal , range = 30 m .
`rArr ((u^(2))/(g)) sin 2 theta = 30 rArr 2 theta = 0.03`
As `sin 2 theta` in small , so take sin `2theta = 2theta`
`2 theta = 0.03 rArr theta = 0.015`