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 22°C. Assume the skin has an area of 2.0 m² and emissivity of 0.97. (o = 5.6696 × 10-8 w/m2 · K4) (a) At what rate is his excess thermal energy dissipated by radiation? (Enter your answer to at least one decimal place.) 136.7 Your response differs from the correct answer by more than 10%. Double check your calculations. W (b) If he eliminates 0.44 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

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 22°C. Assume the skin has an area of 2.0 m² and emissivity of 0.97. (o = 5.6696 × 10-8 w/m2 · K4) (a) At what rate is his excess thermal energy dissipated by radiation? (Enter your answer to at least one decimal place.) 136.7 Your response differs from the correct answer by more than 10%. Double check your calculations. W (b) If he eliminates 0.44 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

Physics for Scientists and Engineers, Technology Update (No access codes included)

9th Edition

ISBN:9781305116399

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter20: The First Law Of Thermodynamics

Section: Chapter Questions

Problem 20.8OQ: Beryllium has roughly one-half the specific heat of water (H2O). Rank the quantities of energy input...

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Beryllium has roughly one-half the specific heat of water (H2O). Rank the quantities of energy input required to produce the following changes from the largest to the smallest. In your ranking, note any cases of equality, (a) raising the temperature of 1 kg of H2O from 20C to 26C (b) raising the temperature of 2 kg of H2O from 20C to 23C (c) raising the temperature of 2 kg of H2O from 1C to 4C (d) raising the temperature of 2 kg of beryllium from 1C to 2C (e) raising the temperature of 2 kg of H2O from -1C to 2C
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 22°C. Assume the skin has an area of 2.0 m2 and emissivity of 0.97. (o = 5.6696 × 10-8 w/m2 · K4) (a) At what rate is his excess thermal energy dissipated by radiation? (Enter your answer to at least one decimal place.) 1.8e2 W (b) If he eliminates 0.44 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.) 3.0e2 W (c) At what rate is energy eliminated by evaporation from the lungs? (Enter your answer to at least one decimal place.) 10.6 W (d) At what rate must the remaining excess energy be eliminated…
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 26°C. Assume the skin has an area of 2.0 m2 and emissivity of 0.97. (σ = 5.6696 10-8 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 0.44 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…
When it rains, water vapor in the air condenses into liquid water, and energy is released. (a) How much energy is released when 0.0318 m (1.25 inch) of rain falls over an area of 2.59×106 m² (one square mile)? (b) If the average energy needed to heat one home for a year is 1.50x1011 J, how many homes could be heated for a year with the energy determined in part (a)? (a) Number (b) Number i i Units Units >
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When someone has a fever, his or her body temperature might increase by as much as 2°C. Suppose this person has a mass of 48 kg. (a) About how much energy is required to raise a person’s temperature this much? The energy required to raise the person’s temperature is ___J (b) What is this energy in food calories? (1 food calorie ≡ 1 Cal ≡ 1000 calories = 1 kcal.) The energy in food calories is ___cal
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