Question

Vishal weighing 80 kgf climbs up a stair of 40 steps each 25 cm high in 4 minutes and Faizan weighing 70 kgf does the same in 5 minutes.
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Answer 1

Answer

(i) Given: m

1

=40kgf,m

2

=30kgf,h

1

=h

2

,t

1

=4minutes=4×60sec,t

2

=3minutes=3×60sec

Comparing work done by them:

Work done by girl

Work done by a boy

=

m

2

gh

2

m

1

gh

1

=

m

2

m

1

=

30

40

=4:3

(ii) Comparing power developed by them:

Power developed by girl

Power developed by boy

=

Work done by girl / time taken to climb up the stairs in seconds

Work done by boy / time taken to climb up the stairs in seconds

=

3×60

1800

4×60

2400

=

4×60

2400

×

1800

3×60

=1:1