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Gasoline (SG=0.72) is flowing through a 6 NPS, schedule 40 pipe at 68F. To measure the flow velocity, a Venturi meter with a 4 " NPS, schedule 40 pipe throat is inserted into the pipe. A manometer is attached across the pipe contraction and uses red manometer oil (SG=0.827). - What is the pressure difference (in psi) across the contraction when there is a height difference of 16 in in the manometer