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

The power is work divided by time. The work is

$$W=mgh.$$

So, the power is

$$P=\frac Wt=\frac{mgh}t=10584\text{ W}.$$