Determine the depth of the well if a stone falling freely into it reaches the surface of the water in 4 seconds

Determine the depth of the well if a stone falling freely into it reaches the surface of the water in 4 seconds. What is the speed of a stone when it hits the surface of the water?

Task data: t (duration of free fall of a stone to the water surface) = 4 s.

Reference values: g (acceleration due to gravity) ≈ 10 m / s2.

1) The depth of the well (distance traveled by this stone): h = g * t2 / 2 = 10 * 42/2 = 80 m.

2) The speed that this stone had at the moment of impact on the water surface: V = g * t = 10 * 4 = 40 m / s.

Answer: The depth of the well is 80 m; this stone at the moment of impact had a speed of 40 m / s.