Air flows at 100oC and 300 kPa in a 1.2-cm-(inside)-diameter tube at a velocity such that a Reynolds number of 15,000 is obtained. The outside of the tube is subjected to a cross-flow of air at 100 kPa, 30oC, and a free-stream velocity of 20 m/s. The tube wall thickness is 1.0 mm. Calculate the overall heat transfer coefficient for this system. What would be the temperature drop of the air inside the tube per centimeter of length.