Air at p=1 atm enters a long tube of length 2.5 m and diameter of 12 mm at an inlet temperature of Tm,i=100oC and mass flowrate of 300 x 10-6 kg/s. A constant heat flux is applied to the air from the tube surface. If the tube surface temperature at the exit is Ts,o=180oC, determine the heat rate entering the tube. Evaluate properties at T=400 K.