For both problems, assume the following average properties for water: Cp=4214 J/kg.K =289 10-6 N.s/m2 k=0.679 W/m.K Pr = 1.8 1. A thin-walled, metallic tube of length L=1m and inside diameter Di=3 mm has its surface maintained at 27C. Water enters the tube at a mass flow rate of 0.015 kg/s and a mean inlet temperature of 97 C. Find the water outlet temperature.

2. A thin-walled, metallic tube of length L=1m and inside diameter Di=3 mm is insulated with a 0.5- mm thick layer of insulation of k=0.05 W/m.K. The outer surface of the insulation is maintained at 27C. Water enters the tube at a mass flow rate of 0.015 kg/s and a mean inlet temperature of 97 C. Explain how this problem is different from problem 1, and show how you would find the outlet temperature of the water (which equations you would use and how, without solving them)