From what height did the stone fall if at the moment of its fall its speed was equal to 30 m / s?

To find the initial height of a given stone, use the formula: h = S = (V ^ 2 – V0 ^ 2) / 2a = V ^ 2 / 2g.

Constants and variables: V – speed at the moment of falling (V = 30 m / s); g – acceleration due to gravity (g ≈ 10 m / s2).

Calculation: h = V ^ 2 / 2g = 30 ^ 2 / (2 * 10) = 45 m.

Answer: The given stone should have fallen from a height of 45 m.