A projectile has a range of `40 m` and reaches a maximum height of `10 m`. Find the angle at which the projectile is fired.

Options

A. `55^(@)`
B. `45^(@)`
C. `60^(@)`
D. `65^(@)`

Answer

B

Explanation

Range of a projectile `R = (u_(0)^(2) sin 2 theta_(0))/(g) = 40 m`
`H = (u_(0)^(2) sin^(2) theta_(0))/(2g) = 10m`
Dividing the two, we get`, (2(sin 2theta_(0)))/(sin^(2) theta_(0)) = 4`
`(4 sin theta_(0) cos theta_(0))/(sin^(2) theta_(0)) = 4`
`rArr tan theta_(0) = 1 rArr theta_(0) = 45^(@)`