1. A duct for an air conditioning system has a rectangular cross section of 2ft by9in. The duct is fabricated from galvanized iron (ɛ= 0.006in). Calculate the pressure drop in

psi for a horizontal 50-ft section of pipe with a flow rate of air of5000cfm at 100 °F and atmospheric pressure (y=0.0709 lbf/ft³; v=1.8×104ft?/sand u=3.96x10Ibf.s/ft?) (Hint: Watch the video “Chapter8-Non-circular duct.mp4")DDz