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(a) At what rate is his excess thermal energy dissipated by radiation? (Enter yo

ID: 694734 • Letter: #

Question

(a) At what rate is his excess thermal energy dissipated by radiation? (Enter your answer to at least one decimal place.)
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(b) If he eliminates 0.41 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.)
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(c) At what rate is energy eliminated by evaporation from the lungs? (Enter your answer to at least one decimal place.)
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(d) At what rate must the remaining excess energy be eliminated through conduction and convection?
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Explanation / Answer

a)

Radiative heat loss rate = (emissivity)()*(body area)*[T_2^4 - T_1^4]

T2 is the body temp in Kelvin and T1 is the average temp of surrounding


= 0.97*5.6696*10^-8*2.0*[310.15^4-294.15^4]

=194.31W

b)

given prespiration = 0.34

evaporation of sweat = 2430

rate is thermal energy dissipated by evaporation of sweat is

= prespiration*evaporation of sweat

= 0.34*2430

=826.2Kj

c)

evaporation from the lungs = (38 kJ/h)

38*0.34 =12.92

d)

80% of the metabolic rate = 2500*80/100 =2000

2000 - 194.31+826.2+12.92 =966.57