Overall, 80% of the energy used by the body must be eliminated as excess thermal energy and needs to be dissipated. The mechanism elimination are radiation, evaporation of sweat (2,430 kJ/kg), evaporation from the lungs (38 kJ/h), conduction, and convection. A person working out in a gym has a metabolic rate of 2,500 kJ/h. His body temperature is 37°C, and the outside temperature 28°C. Assume the skin has an area of 2.0 m² and emissivity of 0.97. (= 5.6696 x 108 W/m²K4) (a) At what rate is his excess thermal energy dissipated by radiation? (Enter your answer to at least one decimal place.) W (b) If he eliminates 0.32 kg of perspiration during that hour, at what rate is thermal energy dissipated by evaporation of sweat? (Enter your answer to at least one decimal place.) W (c) At what rate is energy eliminated by evaporation from the lungs? (Enter your answer to at least one decimal place.) W (d) At what rate must the remaining excess energy be eliminated through conduction and convection? W

Overall, 80% of the energy used by the body must be eliminated as excess thermal energy and needs to be dissipated. The mechanism elimination are radiation, evaporation of sweat (2,430 kJ/kg), evaporation from the lungs (38 kJ/h), conduction, and convection. A person working out in a gym has a metabolic rate of 2,500 kJ/h. His body temperature is 37°C, and the outside temperature 28°C. Assume the skin has an area of 2.0 m² and emissivity of 0.97. (= 5.6696 x 108 W/m²K4) (a) At what rate is his excess thermal energy dissipated by radiation? (Enter your answer to at least one decimal place.) W (b) If he eliminates 0.32 kg of perspiration during that hour, at what rate is thermal energy dissipated by evaporation of sweat? (Enter your answer to at least one decimal place.) W (c) At what rate is energy eliminated by evaporation from the lungs? (Enter your answer to at least one decimal place.) W (d) At what rate must the remaining excess energy be eliminated through conduction and convection? W

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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Question

Overall, 80% of the energy used by the body must be eliminated as excess thermal energy and needs to be dissipated. The mechanisms of
elimination are radiation, evaporation of sweat (2,430 kJ/kg), evaporation from the lungs (38 kJ/h), conduction, and convection.
A person working out in a gym has a metabolic rate of 2,500 kJ/h. His body temperature is 37°C, and the outside temperature 28°C.
Assume the skin has an area of 2.0 m² and emissivity of 0.97. ( = 5.6696 x 108 W/m². K4)
(a) At what rate is his excess thermal energy dissipated by radiation? (Enter your answer to at least one decimal place.)
w
(b) If he eliminates 0.32 kg of perspiration during that hour, at what rate is thermal energy dissipated by evaporation of sweat?
(Enter your answer to at least one decimal place.)
w
(c) At what rate is energy eliminated by evaporation from the lungs? (Enter your answer to at least one decimal place.)
W
(d) At what rate must the remaining excess energy be eliminated through conduction and convection?
W

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