Determine the total mechanical energy of a stone with a mass of 40 g falling from a height of 20 m at a speed of 50 m / s.

Problem data: m (stone mass) = 40 g (in SI m = 0.04 kg); h (height at which the stone is located) = 20 m; V (stone speed) = 50 m / s.

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

The total mechanical energy of the stone in question at the initial moment of time is calculated by the formula: Em = Ek + En = m * V ^ 2/2 + m * g * h.

Let’s make a calculation: Em = 0.04 * 50 ^ 2/2 + 0.04 * 10 * 20 = 58 J.

Answer: At the initial moment of time, the stone will have a total mechanical energy of 58 J.