In a uniform gravitational field `g`, which is acting vertically downward, a ball is thrown at an angle with horizontal such that the initial (immediately after projection) radius of curvature is `8` times the minimum radius of curvature. If angle of projection is `150^(@)`, then find the value of `theta`.

Explanation

Minimum radius of curvature will be at highest point.
Therefore
`(u^(2))/(g costheta)=8 (u^(2)cos^(2)theta)/(g)`
`rArr costheta=(1)/(2)`
`rArr theta=60^(@)`