Hi there!
We can begin by calculating the total time of the ball's projectory:
t = d/v
t = 15/5 = 3 sec
We can use the simplified kinematic equation for time:
t = √2h/g
Rearrange to solve for h:
t² = 2h/g
gt² = 2h
gt²/2 = h
Plug in the values: (g = 9.8 m/s²)
9.8(3)² / 2 = 44.1 m