A ball is thrown from a point O aiming a target at angle `30^(@)` with the horizontal so that the ball hits the target at B but the ball hits at point A, a vertical distance h below B. If the intial velocity of the ball is `20 ms^(-1)` and the horizontal distance between O and C is 10 m. Find the value of h.

Options

A. `(g)/(6)m`
B. `(g)/(10)m`
C. `(g)/(3)m`
D. `(g)/(12)m`

Answer

A

Explanation

In moving horizontal distance 10m, the ball will fall by distance `(1)/(2)g t^(2)`.
`rArr 10 = 20 xx cos 30^(@)t = 20 xx (sqrt(3))/(2)t rArr t = (1)/(sqrt(3)) s`
`AB = h = (1)/(2)g t^(2) = (1)/(2) xx g xx ((1)'/(sqrt(3)))^(2) = (g)/(6)m`