Hint: The ball is free falling independently on its motion to the left. Thus, knowing the height h (together with gravitational acceleration g) is enough to calculate the time ball needs to reach the corner. Than we can use the same fact to calculate initial velocity...

Well done! When we understand the principle of independence of motion, this is an easy task indeed. Thus, this is the minimal velocity. The second minimal velocity we obtain when the ball once hit the right wall and twice the left one...

What is the height of the ball horizontally kicked (see figure)?...if the angle alpha is 45 0 and the coefficient of friction is 0.21. Due to the friction the ball will stop after 1m.

How does an outfielder in baseball know exactly where a fly ball is going to come down?Are these guys that good at geometry or logorythmns with such speed?