Question

A 1.88 -m ( 6 ft 2 in. ) man has a mass of 99 kg, a body surface area of 2.2 m 2 , and a skin temperature of 35.3 ∘ C. Normally, 80 % of the food calories he consumes go to heat; the rest goes to mechanical energy. His emissivity e is 1 because his body radiates almost entirely nonvisible infrared energy, which is not affected by skin pigment. (Careful! His body at 35.3 ∘ C radiates into the environment at 20.0 ∘ C, but the environment also radiates back into his body. The net rate of radiation is P net = P body − P environment . )

To keep his body’s temperature constant, how many food calories should he eat per day if he is in a room at 20.0 ∘ C and he loses heat only through radiation?

Answer 1

Calculation of required food calorie by a person per day to maintain constant body temperature