ICSE Class 10 Physics 2016 Paper

A boy weighing $40\,\mathrm{kg}$ climbs up a stair of 30 steps each $20\,\mathrm{cm}$ high in 4 minute and a girl weighing $30\,\mathrm{kg}$ does the same in 3 minutes. Compare:

Question : 4 of 73

Marks: +1, -0

The power developed by them.

Solution:

Comparing power developed by them:

\frac{\text{ Power developed by boy }}{\text{ Power developed by girl }}

\frac{\text{ Work done by boy/time taken to climbs up the stairs in seconds }}{\text{ Work done by girl/time taken to climbs up the stairs in seconds }}

\;=\; \frac{ {\; \frac{2400}{4 \times 60}} }{ \frac{1800}{3 \times 60} } = \; \frac{2400}{4 \times 60}

\times \; \frac{3 \times 60}{1800}

\;=1: 1

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