Need help with an HVAC question

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Homework Statement:

So I believe I adequately calculated the Reynolds's number (1912~) and I am semi-sure I got the friction loss (hl) * (L/D) * (v^2/2g) = 3.733 ft. I have no idea how to do the 3rd and 4th part of this question.

Relevant Equations:

https://www.chegg.com/homework-help/questions-and-answers/diagram-next-slide-shows-fluid-power-system-hydraulic-press-following-known-volume-flow-ra-q43623298?trackid=Fm-B327r

1. Reynolds number = (Q/A/60) * (diameter) / (3.99 * 10^-5m^2/s) = 1914