Question

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 .

Answer 1

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

Answer 2

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

Answer 3

I just noted your k value I missed it.

Answer 4

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

Answer 5

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.

Answer 6

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

Answer 7

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

Answer 8

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.

Answer 9

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

Answer 10

i got .1399

Answer 11

but i gt it wrong

Answer 12

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

Answer 13

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

Answer 14

i pluged it in still wrong