# Using a winch, they lift a load weighing 5 tons to a height of 5 m.

Using a winch, they lift a load weighing 5 tons to a height of 5 m. Calculate the work that needs to be done for this lift, if the efficiency of the winch is 75

Data: m (mass of the lifted load) = 5 t (in SI m = 5 * 10 ^ 3 kg); h (lifting height) = 5 m; η (efficiency of the used winch) = 75% (0.75).

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

To determine the work expended to lift the load taken, we apply the formula: η = Ap / Az, whence Az = Ap / η = m * g * h / η.

Let’s perform the calculation: Az = 5 * 10 ^ 3 * 10 * 5 / 0.75 = 333.3 * 10 ^ 3 J (333.3 kJ).

Answer: It is necessary to perform work at 333.3 kJ.

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