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Solved: BIO Entropy of Metabolism. An average sleeping
Chapter 20, Problem 38P(choose chapter or problem)
Problem 38P
BIO Entropy of Metabolism. An average sleeping person metabolizes at a rate of about 80 W by digesting food or burning fat. Typically, 20% of this energy goes into bodily functions, such as cell repair, pumping blood, and other uses of mechanical energy, while the rest goes to heat. Most people get rid of all this excess heat by transferring it (by conduction and the flow of blood) to the surface of the body, where it is radiated away. The normal internal temperature of the body (where the metabolism takes place) is 37°C, and the skin is typically 7 C° cooler. By how much does the person’s entropy change per second due to this heat transfer?
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QUESTION:
Problem 38P
BIO Entropy of Metabolism. An average sleeping person metabolizes at a rate of about 80 W by digesting food or burning fat. Typically, 20% of this energy goes into bodily functions, such as cell repair, pumping blood, and other uses of mechanical energy, while the rest goes to heat. Most people get rid of all this excess heat by transferring it (by conduction and the flow of blood) to the surface of the body, where it is radiated away. The normal internal temperature of the body (where the metabolism takes place) is 37°C, and the skin is typically 7 C° cooler. By how much does the person’s entropy change per second due to this heat transfer?
ANSWER:Solution 38P
80 W means 80 Joule of energy per second.
20% of this energy is used up and rest 80% goes to heat. Therefore, the amount of energy going as heat
This heat corresponds to the internal temperature of of the body.
Therefore,