The crane has to lift 3000 tons of building materials to a height of 9m within 8 hours of a working day.

The crane has to lift 3000 tons of building materials to a height of 9m within 8 hours of a working day. What is the power of the crane engine if the efficiency of the installation is 60%.

Given: t (duration of crane operation) = 8 h (in SI t = 28800 s); m (mass of the raised building materials) = 3000 t (in SI m = 3 * 10 ^ 6 kg); h (lifting height of materials) = 9 m; η (installation efficiency) = 60% (0.6).

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

To determine the engine power of the crane used, we apply the formula: η = Np / Nk = (A / t) / Nk = (m * g * h / t) / Nk and Nk = m * g * h / (t * η).

Calculation: Nk = 3 * 10 ^ 6 * 10 * 9 / (28800 * 0.6) = 15625 W ≈ 15.6 kW.