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anonymous

  • one year ago

A carpenter builds a solid wood door with dimensions 1.95 m × 0.91 m × 6.0 cm . Its thermal conductivity is k=0.120W/(m⋅K). The air films on the inner and outer surfaces of the door have the same combined thermal resistance as an additional 1.9 cm thickness of solid wood. The inside air temperature is 23.0 ∘C , and the outside air temperature is -5.00 ∘C .

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  1. anonymous
    • one year ago
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    What is the rate of heat flow through the door? Express your answer using two significant figures.

  2. anonymous
    • one year ago
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    what's the specific heat capacity of the material in question?

  3. anonymous
    • one year ago
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    I just noted your k value I missed it.

  4. anonymous
    • one year ago
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    Alrigth you are aware that measurement of temperature is in Kalvin scale.

  5. anonymous
    • one year ago
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    Think of the heat transfer from inside the door to the surface door as an act of thermal equilibrium. All the objects in contact with different temperatures try to reach equilibrium.

  6. anonymous
    • one year ago
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    First of all you need to calculate the surface of the door and volume of the door.

  7. anonymous
    • one year ago
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    And set everything to meters rather than centimeters because k value is expressed with meters/ Are you reading this? You seem unresponsive.

  8. anonymous
    • one year ago
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    This is a problem on how different objects in contact with different temperatures come to thermal equilibrium depending on the surface as well as the volume. Note that it all depends on the potential thermal energy at play.

  9. anonymous
    • one year ago
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    You can use Fourier's law \[Q=\frac{ kA }{ t }(T_{high}-T_{low})\] Q = heat rate k = thermal conductivity A = cross-sectional area of the surface perpendicular to the flow. Looks like that's 1.95 m by 6.0 m t = thickness of the surface. In this case you'd have to add an extra 1.9 cm to the 0.91 m to get the total thickness of the door

  10. anonymous
    • one year ago
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    i got .1399

  11. anonymous
    • one year ago
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    but i gt it wrong

  12. anonymous
    • one year ago
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    check your units. Make sure all the lengths are in meters

  13. anonymous
    • one year ago
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    Q = (0.12 W/m-K)(1.95 m)(6.0 m)(23 °C - (5 °C))/(0.91 m + 0.019 m)

  14. anonymous
    • one year ago
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    i pluged it in still wrong

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