Question

A crane lifts 1, 800 kg load os scrap metal to a distance of 12 m in 20 s. How much power is delivered to the road?

Answer 1

$$P=\dfrac{W}{t}=\dfrac{mgh}{t},$$ $$P=\dfrac{1800\ kg\cdot9.8\ \dfrac{m}{s^2}\cdot12\ m}{20\ s}=10584\ W=10.6\ kW.$$