What is the efficiency of a crane that lifts a load of m = 3 tons to a height of 10 m in 30 s?

What is the efficiency of a crane that lifts a load of m = 3 tons to a height of 10 m in 30 s? crane motor power Rsatrach = 20kW

To find the value of the efficiency of the specified crane, we will use the formula: η = Ppol / Psatr = (A / t) / Psatr = m * g * h / (t * Psatr).

Variables and constants: m is the mass of the cargo (m = 3 t = 3 * 10 ^ 3 kg); g – acceleration due to gravity (g ≈ 10 m / s2); h – height (h = 10 m); t – elapsed time (t = 30 s); Rzatr – consumed engine power (Rzatr = 20 kW = 20 * 10 ^ 3 W).

Calculation: η = m * g * h / (t * Rsatr) = 3 * 10 ^ 3 * 10 * 10 / (30 * 20 * 10 ^ 3) = 0.5 (50%).

Answer: The efficiency of this crane is 50%.