Power tells you how quickly energy is transferred, or how quickly work is done. A powerful motor does a lot of work in a short time. A weak motor needs longer to do the same job.
The equation is: power = work done ÷ time taken. In symbols, P = W ÷ t. Power is measured in watts (W), work done in joules (J) and time taken in seconds (s). The time must be in seconds, so change minutes to seconds before you start.
Worked example: a crane does 6000 J of work lifting a load in 12 s. Power = 6000 ÷ 12 = 500 W. The same equation can be rearranged to find work done: W = P × t. A 500 W motor running for 10 s does 500 × 10 = 5000 J of work.