Q. A man is riding on a cycle with velocity 7.2 km/h up a hill having a slope 1 in 20. The total mass of the man and cycle is 100 kg. The power of the man is
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Solution:
Given, $ v=7.2\,km{{h}^{-1}} $ $ =7.2\times \frac{5}{18}=2\,m\text{/}s $ Slope is given 1 in 20
i.e, $ \sin \theta =\frac{1}{20} $ For the upward motion to the cyclist. $ F=mg\,\sin \theta $ $ \therefore $ Power of the man, $ P=F\times v=mg\,\sin \theta \times v $ $ =100\times 9.8\times \frac{1}{20}\times 2=98\,W $
