Question

The human body converts internal chemical energy into work and heat at rates of 60 to 125 W (called the basal metabolic rate). This energy comes from food and is usually measured in kilocalories [1 kcal = 4.186 kJ]. (Note that the nutritional `Calorie' listed on packaged food actually equals 1 kilocalorie). How many kilocalories of food energy does a person with a metoblic rate of 109.0 W require per day? (Assume 100 percent efficiency.)

Answer 1

109.0 W
Power = Energy / time
109.0 = Energy / (24*3600)
Energy = 9417600 J
Energy = 9417.6 kJ

1 Kcal = 4.186 kJ

Total kilocalories of food energy needed = 9417.6 / 4.186
Total kilocalories of food energy needed = 2249.785 Kcal