Answer:
5.72 seconds
848.27 m/s
97.94 m
Explanation:
t = Time taken
u = Initial velocity = 15 m/s
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 9.81 m/s²
Time taken to reach maximum height is 0.97 seconds
So, the stone would travel 11.47 m up
So, total height stone would fall is 75+11.47 = 86.47 m
Total distance travelled by the stone would be 75+11.47+11.47 = 97.94 m
Time taken by the stone to travel 86.47 m to the water is is 4.2 seconds
The stone reaches the water after 4.2+1.52 = 5.72 seconds after throwing the stone
Speed just before hitting the water is 848.27 m/s