7.4 Exercise 12

(a) What is the average useful power output of a person who does $6.00 \times 10^{6} \text{J}$ of useful work in 8.00 h? (b) Working at this rate, how long will it take this person to lift 2000 kg of bricks 1.50 m to a platform? (Work done to lift his body can be omitted because it is not considered useful output here.)