A 4000-foot ductile iron carries a flow rate of 50 cfs. The pipe has a 20-inch diameter with a 0.75 wall thickness and is free to move longitudinally. There is

a gate valve just upstream of the pipe outlet. If the gate valve is closed in the 1.25 seconds, what is the maximum water hammer pressure? Explanation: Why was the valve closure time included in the problem information?