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InterviewSolution
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How much metres can a 50 kg man climbs by using the energy from a slice of a bread which produces 420 kJ heat? Assuming that the human body effciency working is `30%`. Use `g=10 m//s^(2)`. |
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Answer» Let h be the height climbed by man. increase in PE of man = `mgh = 50 xx 10 xx h j` Heat produced , `H = 420 xx 1000 j` `=4.2 xx 10^(5) J` effciency of man = `30%`, so heat energy utilized by man in doing work is `=30/100 xx 4.2 xx 10^(5) = 12.6 xx 10^(4) J` Now, increase in PE = heat energy utilized `50 xx 10 xx h = 12.6 xx 10^(4)` or `h=(12.6 xx 10^(4))/(50 xx 10) = 252 m`. |
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