Acomposite plane wall consists of a 5-in.-thick layer of insulation (ks = 0.029 btu/h*ft*°r) and a 0.75-in.-thick layer of siding (ks = 0.058 btu/h*ft*°r). the inner temperature of the insulation is 67°f. the outer temperature of the siding is -8°f.
determine at steady state:
(a) the temperature at the interface of the two layers, in °f, and (b) the rate of heat transfer through the wall in btu/h*ft^2 of surface area.