A person of mass 60 kg wants to lose 5 kg 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 on expending 7000 kilo calories, how many times must he go up and down to reduce his weight by 5 kg ?

A person of mass 60 kg wants to lose 5 kg by going up and down a 10 m

1.	A person of mass 60 kg wants to lose 5 kg 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 on expending 7000 kilo calories, how many times must he go up and down to reduce his weight by 5 kg ?
Answer» Solution :Height of the stairs H = 10 m Work done to burn 1 kg of fat = 7000 K cal `therefore` Work done to burn 5 kg of fat =5 x 7000 = 35000 k cal Work done towards burning of fat in up and down the stairs, `=mgh+1/2mgh` `=3/2mgh` `=3/2xx60xx10xx10` =9000 J `=9000xx1/4.2` cal =2142.85 cal `therefore` For energy of 2142.85 cal one trip (up and down) of stairs needed Hence , for energy of `35xx10^6` cal N trip (up and down) of stairs needed. `therefore n=(35xx10^6)/(2142.85)=0.01633xx10^6` =16330 TIMES