Question

power required by a boy of mass 30 kg to run up a stair case of 40 steps in 10 seconds is(height of each step is 15 cm)(take g=10m/s2

Answer 1

Mass of the boy = 30 kg
Number of steps = 40
Height of each step = 15 cm
Therefore height of 40 steps = 15*40 = 600 cm = 6 m
Time taken to run up = 10 s

Power = (mass * gravity * Height)/time
           = 30*10*6/10
           = 180 W

The power required = 180 W


Hope this helps you.

Answer 2

Hey !!

Total height reached by boy

        = 40 × $\frac{15}{100} = 6 cm$

As we know,

       Power = Work done / time = $\frac{mgh}{t}$

      = 30 × 10 × 6 / 10

Power = 180 W

Good luck !!