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
Answer:The buoyant force doesn't depend on the overall depth of the object submerged. In other words, as long as the object is fully submerged, bringing it to a deeper and deeper depth will not change the buoyant force. This might seem strange since the pressure gets larger as you descend to deeper depths.:
Planck's constant is 4.39048042 × 10-67 m4 kg2 / s2.
<span>Velocity is a vector and it has both speed and direction. It takes a force to change direction just as it does to change speed</span>. In order to have a constant velocity the object must maintain a constant direction and speed. Hope this answers the questions. Have a nice day.