Part of a vertical piping system consists of 8 ft of 4 in diameter, connected to 8 ft of 3 in diameter above, and connected to 8 ft of 2 in diameter above that. Water at 60 F flows up the pipe (no downward flow occurs).
A) Neglecting friction, find the difference in water pressure (psi) between the two ends what the flow rate is 150 gallons per minute (gpm).
B) what is the minimum possible value for this pressure difference, and under that circumstances does it occur?