The evaporation of perspiration is the primary mechanism for cooling the human body. Determine the amount of water you will lose when you bake in the sun on the beach for an hour. Use a value of 900 W/m2 for the intensity of sunlight, assume that the area of your body exposed to the sun is 0.61 m2 and that your skin temperature is 37°C, and note that the energy required to evaporate a liquid at a particular temperature is approximately equal to the sum of the energy required to raise its temperature to the boiling point and the latent heat of vaporization (determined at boiling point).
the formula i was trying to use is stephan's law but that didnt seem to work.
Any help with this problem would really help me out, thanks!
2007-04-10 14:53:54 · 2 answers · asked by Kacey L 1 in Science & Mathematics ➔ Physics
900 W/sq.m x .61 sq. m = 549 W x 3.415 = 1875 BTU/Hr
to heat water on the skin from 98.6 to 212 Deg F = cp(T2-T1) = 1 x 113.4 = 113.4 BTU/Lb
to evaporate water off the skin =hfg = 970.3 BTU/LB
113.4 + 970.3 = 1083.7 BTU/Lb
1875 BTU/Hr/1083BTU/Lb = 1.73 Lb/Hr
Check the math
2007-04-10 16:31:08 · answer #1 · answered by gatorbait 7 · 0⤊ 0⤋
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2017-02-08 21:59:39 · answer #2 · answered by ? 4 · 0⤊ 0⤋