Question

A boy weighing 350N climbs up the steps,each 20cm high in 1 minute. Calculate : (i) the work done, and (ii) the power spent.

Answer 1

Work done = Force × Displacement = 350N × 20/100 = 70 J

Power = Work / time = 70 J /60 s = 1.16 W

Answer 2

Hey there!

Given,

Weight = 350 N

Height = height of one step x no. of steps

          = 0.2 x 30

          = 6 m

We know,

Work done = P.E = mgh

Work done = 350 x 6 = 2100 J

And,

Power = Work done/Time

          = 2100/60              [ 1 min = 60 sec.]

          = 35 W

Hope It Helps You!