A) How much thermal energy must be removed from your body per second to keep you

Question

A) How much thermal energy must be removed from your body per second to keep your temperature constant?
B) If 50% of this energy loss is caused by evaporation, how much water do you lose per second?
C) How much water do you lose in 3 hours?
(My professor worded this question pretty weird, so I decided to label the different parts myself.) When you run a marathon, the opposing force that air exerts on you does -150 J of work each second. You convert 1000 J of internal chemical energy to thermal energy each second. (b) If 8) 50% of this energy loss is caused by evaporation, how much water do you lose per second? (c) How much water do you lose in 3 h? c) (10%) How much thermal energy must be removed from your body per second to keep your temperature constant? (1096) If 50% of this energy loss is via evaportion, how much water do you lose in 3 h? 2.

Explanation / Answer

Work done dw=150 J

Internal energy du=1000 j

(A) and

Now we apply first law of thermodynamics to find heat energy

dQ=du+dw=1000+150=1150 J

1150 joules heat is removed from the body to keep temperature is constant

(B) ans:

50% of energy is loss via evaporation =50/100×1150 =575 J

Therefore we apply latent heat of evaporation condition

Q=M.L {L=latent heat of evaporation =334000 J/s

575=M×334000

M=0.00172 kg

The mass of water loss per sec M=0.00172 kg

(C) and

3 hours=10800 sec

The amount of water loss in 3 hours

=10800×0.00172=18.576 kg

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