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Question
It takes 20 s for a girl A to climb up the stairs while girl B takes 15 s for the same job. Compare the power spent by then.
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Solution
Power = `"Work done"/"Time taken "` = `"Energy" /"Time"`
= `"Power of A "/ "Power of B"` = `(" Energy "/ t_1 )/("Energy "/ t_2)`
= `1/t_1` ' `t_2/1` =`15/20`
= `3/4` = 3 : 4
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