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Thermal conductivity 
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#1
Nov1707, 12:05 AM

P: 41

1. The problem statement, all variables and given/known data
A mountain climber wears a goose down jacket 3.28 cm thick with total surface area 1.10 m2. The temperature at the surface of the clothing is 19.3°C and at the skin is 36.0°C. Determine the rate of heat flow by conduction through the jacket assuming it is dry and the thermal conductivity, k, is that of down. Part 2: Determine the rate of heat flow by conduction through the jacket assuming the jacket is wet, so k is that of water and the jacket has matted down to 0.462 cm thickness. 2. Relevant equations thermal conductivity of goose down is .025 J/(mKs) thermal conductivity of water is .561W/(mKs) phi dot = KA (delta T/delta X) K is goose down (.025 j/smk) A is area T is temperature x is distance heat flows Part 2 The rate of heat flow= (the rate of heat flow you found in part 1) x (k water/ k goose down) x (thickness of goosedown/ thickness of wet jacket) 3. The attempt at a solution .025*(.0328*1.10)*(36+19.3/.0328) I get the rate is 1.52 W, yet it is the wrong answer. If I had that answer I could use it to get part 2 where I would do the following rate=rate1*(.561/.025)*(.0328/.00462) Please let me know what I am doing wrong! Thank you! 


#2
Nov1707, 01:24 AM

HW Helper
P: 1,982

Why is the distance between the two surfaces in the numerator? Delta_x should be in the bottom.



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