A ball is thrown from a point in level with velocity `u` and at a horizontal distance `r` from the
Channel: Doubtnut
Date: 2020-07-26

A ball is thrown from a point in level with velocity `u` and at a horizontal distance `r` from the top os a tower of height `h`.  How must the speed and angle of the projection of the ball be related to `r` in order that the ball may just go grazing the top edge of the tower ?