Question

A boy of mass 40kg runs up a flight of 30steps each step is 150mm in 6s.Find the average power developed by the boy.(g=10ms²)

Answer 1

1) Determine the potential energy of the boy:

$$E=mgH=mg(nh).$$

2) Work done by the boy is equal to the energy:

$$W=E=mgnh.$$

3) The power is work divided by time:

$$P=\frac{W}{t}=mgnh/t=294\text{ W}.$$