Question

a man whose weight is 500 N moves up 15 steps each of height 15cm in 40 seconds of time calculate the power used in climbing those staris.

Answer 1

power = $\frac{work done}{time}$
work done = weight ×no.of steps×height of each step
1 cm = 1/100 mt
work done = 500×15×15/100 = 1125
power = $\frac{112500}{40}$ = 28.125 watt

Answer 2

P=mgh/t
h=15/100*40=6m
W=500N
t=40s

=500*10*6/40
=30000/40
=750watt

So the power used by him to climb the steps is 750watt