Figure 2 shows water at 70 C enter a thin wall tube with all parameters given in the figure, and air at To = 20 C is in cross flow over the tube. Assuming the thermal resistance of the tube wall is negligible, determine the tube length. Air T = 20 C V =20m/s Tube D = 0.05 m Tm.o= 30C water mi = 0.215 kg/s Tmi = 70 C Figure 2 A thin wall tube (24 marks)