Question

A man whose mass is 50 kg climbs up 30 steps of a stair in 30 s. If each step is 20 cm high, calculate the power used in climbing stairs.​

Answer 1

Question :

A man whose mass is 50 kg climbs up 30 steps of a stair in 30 s. If each step is 20 cm high, calculate the power used in climbing stairs.​

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Answer :

Given,
→ Mass of man=50 Kg
→ g=10m/s2

1st thing to do,

= 20cm Þ 30 steps = 600 cm = 6m Þ h=6m

w= mgh Þ 
w= 50 x 10 x 6

♣ t=30sec Þ 
p = w/t Þ 
p=50x10x6/30 
Þ =100 W

Answer 2

In climbing the stairs, his gravitational potential energy increases.

P.E. = m * g * h = 50 * 9.81 * (30 * 0.2) = 2943 Joules

He does this in 30 seconds, so the rate of increase of energy is 2943 / 30 Joules/second

=98.1 Watts