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A person of mass 60 kg wants to lose 5kg...

A person of mass 60 kg wants to lose 5kg by going up and down a 10 m high stairs. Assume he burns twice as much fat while going up than coming down. If 1 kg of fat is burnt of expending 7000 k cal, how many times must he go up and down to reduce his weight by 5 kg ?

Text Solution

Verified by Experts

Given, `" "` height of the stairs = h= 10 m
Energy produced by burning 1 kg of fat = 7000 kcal
`therefore` Energy produced by burning 5 kg of fat = `5xx7000` = 35000 kcal
`" "=35xx10^(6)` cal
Energy utilised in going up and down one time
` " "=mgh+(1)/(2)mgh= (3)/(2)mgh`
`" "(3)/(2)xx60xx10xx10`
`" "=9000 J=(9000)/(4.2)=(3000)/(1.4) ` cal
`therefore` Number of times, the person has to go up and down the stairs
`" "=(35xx10^(6))/((3000//1.4))=(3.5xx1.4xx10^(6))/(3000)`
`" "16.3xx10^(3)` times
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