Suppose an experiment is conducted as follows: Air at 300 K enters a smooth tube of 0.1 m in (inner) diameter and 6 m in length with the mass flow rate of 0.002 kg/s. A constant heat flux is imposed and the outside tube wall is thermally insulated from the atmosphere. The exit air temperature is measured to be 350 K.
(1) Find the total heat flux from the tube to the air.
(2) Find the heat transfer coefficient at the exit.
(3) Estimate the wall temperature at the exit.