Question

If in case in a well a boy throws ball at h m height above the water level and a sound of splash comes. In how much time the boy will hear the sound if speed of sound is u?​

Answer 1

$\sqrt{2gh} + \frac{h}{u}$

The first term is the time taken for the ball to actually reach the water.

It's assumed that there is no delay between the ball striking the water and the emanation of a splashy-splashy sound (._.).

The second term is the time taken for the sound to travel back up.