Cru de oil is flow ing ve rtically downward through $60$ m of

DN $25$ Schedule $80$ steel pipe at a velocity of $0\mathrm{.}64$ m$/$s$.$ The

oil has a specific gravity of $0\mathrm{.}86$ and is at $0\backslash$deg C$.$ Calculate

the pressure difference between the top and bot tom of the

pipe.