Air at 20°c (1 atm) enters into a 5-mm-diameter and 10-cm long circular tube at an average velocity of 5.4 m/s. the tube wall is maintained at a constant surface temperature of 160°c. determine the convection heat transfer coefficient and the outlet mean temperature. evaluate the air properties at 50°c. the properties of air at 50°c are: ρ = 1.092 kg/m3 μ = 1.963*10-5 kg/m∙s k = 0.02735 w/m∙k cp = 1007 j/kg∙k v = 1.798 *10−5 m2/s μs = 2.420*10−5 kg/m∙s pr = 0.7228