An aeroplane is travelling horizontally at a height of 2000 m from the ground. The aeroplane, when at a point P, drops a bomb to hit a stationary target Q on the ground. In order that the bomb hits the target, what angle `theta` must the line PQ make with the vertical ? (`g = 10 ms^(-2))`

Options

A. `15^(@)`
B. `30^(@)`
C. `90^(@)`
D. `45^(@)`

Answer

D

Explanation

Let t be the taken by bomb to hit the target.
`h=2000=1/2g t^(2)rArr t=20` sec
`R=ut=(100)(20)=2000 m`
`:' tan theta=R/h=2000/2000=1 rArr theta=45^(@)`