A mountain climber wears a goose down jacket 3.5cm thick with total surface area 1.2m2. The temperature at the surface of the clothing is –20oC and at the skin is 34oC. Determine the rate of heat flow by conduction through the jacket?
(a) Assuming it is dry and the thermal conductivity k is that of down, and
(b) Assuming the jacket is wet, so k is that of water and the jacket has matted to 0.50 cm thickness.