To find the height from which a given body should begin its free fall, we will use the law of conservation of energy: Ek = m * V ^ 2/2 = En = m * g * h, whence h = V ^ 2 / 2g.
Variables and constants: V – the speed that the body developed before hitting the ground (V = 9.8 m / s); g – acceleration due to gravity (g ≈ 9.8 m / s2).
Calculation: h = V ^ 2 / 2g = 9.8 ^ 2 / (2 * 9.8) = 4.9 m.
Answer: The original height was 4.9 m.
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