A weird physics question????

Question

Walking a 3 km/h requires an energy expenditure rate of about 200 w. How far would you have to walk to "burn off" a 300-kcal hamburger? ...... i thought it was 24 km

Answer 1

24 km?! at the speed u r talking about is 8 hrs. then why we do we eat more than the hamburger u mentioned during the day?

300kcal = 300*1000*4.2 joules= 1260000j

the power or the rate=200 watt

as power=energy/time

so 200=1260000/t

so t=6300 sec = 1.75 hrs to exert the energy

so the distance to be walked is 1.75*3= 5.25 km

BY THE WAY: i didn't mean to insult but to give u a hint how to be sure of ur answer.