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 kilocalories, 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 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 kilocalories, how many times must he go up and down to reduce his weight by 5 kg?

Answer:

According to the question, the height of the stairs is

h = 10 m

And the work done to burn 5 kg of fat is

W = (5)(7000 × 103)(4.2)

W = 147 × 106 J

Therefore, the work done towards burning of fat in one trip can be written equal to

= mgh + 1/2 mgh

= 3/2 mgh

= (3/2)(60)(10)(10)

= 9 × 103 J

Therefore, 16.3 × 103 times is the number of trips required