[填空题]
A mountain climber wearsd ijg*js9j 1x.lp 9m6or -c 0clnd,vy5)xjz 6q a goose down ja2nxrq c:hz,u l3a b31pf5t/wkcket 3.5 cm thick with total surface area 5u q/3lr kc b1p,nxwfz2 ah3:t$1.2\,m^2$ The temperature at the surface of the clothing is -20$^{\circ}C $ and at the skin is 34$^{\circ} C$. Determine the rate of heat flow by conduction through the jacket
(a) assuming it is dry and the thermal conductivity k is that of down, W
(b) assuming the jacket is wet, so k is that of water and the jacket has matted to 0.50 cm thickness. W
