Question

A person weighing 70 kg runs up a flight of 30 steps in 35 sec . What is the piwer of the person ,if each step is 20cm high

Answer 1

Given:

A person weighing 70 kg runs up a flight of 30 steps in 35 sec .

To find:

Power delivered by the person if each step is 20 cm high.

Calculation:

Total height achieved by the man in the given time interval is :

$\sf{ = no. \: of \: steps \times step \: height}$

$\sf{ = 30 \times 20}$

$\sf{ = 600 \: cm}$

$\sf{ = 6 \: m}$

Now , total work done is equal to :

$\sf \therefore \: work = m \times g \times h$

$\sf = > \: work = 70 \times 10 \times 6$

$\sf = > \: work = 4200 \: joule$

Now , power is equal to :

$\sf \therefore \: power = \dfrac{work}{time}$

$\sf = > \: power = \dfrac{4200}{35}$

$\sf = > \: power = 120 \: watt$

So, power delivered by man is 120 watt.