Question

c) it takes 45 s for a girl A to climb up the stairs while girls B takes 60s
for the same job. Compare
(1) Work done
(1) Power spent by them
(1) Convert 1 MW = _____ W

Answer 1

Given:

It takes 45 s for a girl A to climb up the stairs while girls B takes 60s for the same job.

To find:

• Work done
• Power spent by them
• Convert 1 MW = _____ W

Calculation:

Since , both girls (assuming same mass) climb the stairs to reach the same height above the Earth's surface , they perform equal amount of work.

$\sf \therefore \: W_{A} = W_{B} = W \: \: \: \: \: \: ....(i)$

Now, we know that power is defined as the work done per unit time :

By girl A , power delivered is W/45 watt

By girl B , power delivered is W/60 watt

So, ratio of power delivered is :

$\sf \therefore \: P_{A} : P_{B} = \dfrac{W}{45} : \dfrac{W}{60}$

$\sf \implies \: P_{A} : P_{B} = 60 : 45$

$\sf \implies \: P_{A} : P_{B} = 4: 3$

Now, let's convert 1 M-watt to watt unit :

$\boxed{ \therefore \: \sf \: 1 \: M - watt = {10}^{6} \: watt}$

Hope It Helps.