Engineering, 16.11.2020 16:40 galayeet
(35-39) A student travels on a school bus in the middle of winter from home to school. The school bus temperature is 68.0° F. The student's skin temperature is 94.4° F. Determine the net energy transfer from the student's body during the 20.00 min ride to school due to electromagnetic radiation. Note: Skin emissivity is 0.90, and the surface area of the student is 1.50m2.
Answers: 2
), measured in BTU per hour, is represented by this formula:
(1)
- Emissivity, dimensionless.
- Surface area of the student, measured in square feet. 
- Stefan-Boltzmann constant, measured in BTU per hour-square feet-quartic Rankine.
- Temperature of the student, measured in Rankine.
- Temperature of the bus, measured in Rankine. 
, 
, 
, 
and 
, then the heat transfer rate due to electromagnetic radiation is:![\dot Q = (0.90)\cdot (16.188\,ft^{2})\cdot \left(1.714\times 10^{-9}\,\frac{BTU}{h\cdot ft^{2}\cdot R^{4}} \right)\cdot [(554.07\,R)^{4}-(527.67\,R)^{4}]](/tpl/images/0900/7418/24bcc.png)
(2)
is the heat transfer time, measured in hours.
, then the net energy transfer is:
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(35-39) A student travels on a school bus in the middle of winter from home to school. The school bu...
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