Chapter 19, Problem 72GP

A mountain climber wears a goose-down jacket 3.5 cm thick with total surface area 0.95 m². The temperature at the surface of the clothing is — 18°C and at the skin is 34°C. Determine the rate of heat flow by conduction through the jacket (a) assuming it is dry and the thermal conductivity k is that of goose down, and (b) assuming the jacket is wet, so k is that of water and the jacket has matted to 0.50 cm thickness.