A) How much thermal energy must be removed from your body per second to keep you
ID: 1522392 • Letter: A
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