4. A hiker is wearing wool clothing of 0.50-cm thickness to keep warm. Her skin temperature is 35°C
and the outside temperature is 4.0°C. Her body surface area is 1.2 m2. (a) If the thermal conductivity
of wool is 0.040 W/(m=K), what is the rate of heat conduction through her clothing? (b) If the hiker is
caught in a rainstorm, the thermal conductivity of the soaked wool increases to 0.60 W/(m=K) (that of water). Now what is the rate of heat conduction?
