Nitrogen flows at steady state through a horizontal, insulated pipe with an inside diameter of 1.5 (in). A pressure drop results from flow through a partially opened valve. Just upstream from the valve the pressure is 100 (psia), the temperature is 120(F ), and the average velocity is 20(ft)s1. If the pressure just downstream from the valve is 20(psia), what is the temperature? Assume for air that PV/T is constant, CV=(5/2)R, and CP=(7/2)R. (Values for R, the ideal gas constant, are given in [M] App. A.)