The 8-mm-thick bottom of a 220-mm-diameter pan may be made from aluminum (k = 240 w/m ⋅ k) or copper (k = 390 w/m ⋅ k). when used to boil water, the surface of the bottom exposed to the water is nominally at 110°c. if heat is transferred from the stove to the pan at a rate of 600 w, what is the temperature of the surface in contact with the stove for each of the two materials?

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.