(a) A boy throws several balls out of the window of his house at different angles to the horizontal. All balls are thrown at speed `u = 10 m//s` and it was found that all of them hit the ground making an angle of `45°` or larger than that with the horizontal. Find the height of the window above the ground [take `g = 10 m//s^(2)]`
(b) A gun is mounted on an elevated platform AB. The distance of the gun at A from the edge B is `AB = 960 m`. Height of platform is `OB = 960 m`. The gun can fire shells with a velocity of `u = 100 m//s` at any angle. What is the minimum distance (OP) from the foot of the platform where the shell of gun can reach ?

Answer

(a) `5m` (b) `480 m`