Two balls are projected simultaneously from the top of a tall building. The first ball is projected horizontally at speed `u_(1) = 10 m//s` and the other one is projected at an angle `theta = tan^(-1) ((4)/(3))` to the horizontal with a velocity `u_(2). [g = 10 m//s^(2)]`

(a) Find minimum value of `u_(2) (= u_(0))` so that the velocity vector of the two balls can get perpendicular to each other at some point of time during their course of flight. ltbr? (b) Find the time after which velocities of the two balls become perpendicular if the second one was projected with speed `u_(0)`.

Answer

(a) `u_(0) = 37.5 m//s` (b) `t = 1.5 m//s`