A boy of mass 50 kg runs up a staircase of 45 steps in 9 s. If the height of each step in 15 cm, find his power. Take `g=10ms^(-2)`.

Explanation

Weight of the boy `mg=50kgxx10ms^(-2)`
`=500N`
Height of the staircase `h=45x(15)/(100)m=6.75m`
Time taken to climb `t=9s`
Power `P=("Work done ")/("Time taken")`
`=(mgh)/(t)`
`=(500Nxx6.75m)/(9s)=375W`
Power is 375.