Consider steady-state conditions for one-dimensional conduction in a plane wall having a thermal conductivity k 50 W/m K and a thickness L 0.25 m, with no internal heat generation. Determine the heat flux and the unknown quantity for each case and sketch the temperature distribution, indicating the direction of the heat flux. Case T1(C) T2(C) dT/dx (K/m) 1 50 20 2 30 10 3 70 160 4 40 80 5 30 200

Steel balls 12 mm in diameter are annealed by heating to 1150 k and then slowly cooled to 400 k in an air att 325 k and h -20 w/m2 k. assume the properties of the steel to be k- 40 w/m k, p 7800 kg/m3, and cp 600 j/kg k. a. determine whether lumped system method can be used to analyze this problem and if so why" b. determine the time required for the cooling process. c. determine the total amount of heat lost from each ball to the ambient air