How much hight above the ground a mancan throw a ball if he is able to throw the same ball upto maximum distance of `60 m?

Explanation

Her, `R _(max)=60 m`.
As, `R_(max) =u^(2) /g , so 60 =u^(2)/g` …(i)
Let (h) be the maximum height attained by the ball.
Taking vertical upward motion of ball upto maximum height (h), we have
`u&(y) =u, a)(y) =- g, u_(y) =0, y=0`
As v_(y)^(2) =u_(y)^(2) +2 a)(y) y`
:. 0=u^(2) +2 (-g) h`
or `h=u^(2)/(2 g) =1/2 xx 60 =30 m`.