Gasoline flows through a long underground pipeline at a temperature of 15ºc. two pumping stations are located 13 km apart, at the same elevation. the pipeline is made from stainless steel piping 0.6 m in diameter, but age and corrosion have increased the roughness to (approximately) that of galvanized iron. the pressure drop between the pumping stations is 1.4 mpa. find the mass flow rate of gasoline.