An extruder barrel has a diameter of 5 in and a length of 12 ft. It screw has a channel depth of 0.3 in, and rotates at 50 rev/ min. The plastic melt has a velocity of ?100 ×10?^(-4) lb-sec/?in?^2 . The die characteristic is Q_x = 0.0015p where p is the head pressure in psi. Determine the flight angle that maximizes the flow rate Q_x and graph it.