## 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 .

1. anonymous

What is the rate of heat flow through the door? Express your answer using two significant figures.

2. anonymous

what's the specific heat capacity of the material in question?

3. anonymous

I just noted your k value I missed it.

4. anonymous

Alrigth you are aware that measurement of temperature is in Kalvin scale.

5. anonymous

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

First of all you need to calculate the surface of the door and volume of the door.

7. anonymous

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

8. anonymous

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

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

i got .1399

11. anonymous

but i gt it wrong

12. anonymous

check your units. Make sure all the lengths are in meters

13. anonymous

Q = (0.12 W/m-K)(1.95 m)(6.0 m)(23 °C - (5 °C))/(0.91 m + 0.019 m)

14. anonymous

i pluged it in still wrong