Glycerin flows through a $2-$inch type K straight copper tube at $25$ degrees Celsius, at a rate of $250$ liters$/$min$.$ Calculate:

a$)$ The Reynolds Number.

b$)$ The value of the friction coefficient.

c$)$ The pressure difference between two points separated by $30$ m$,$ if the first point is $0\mathrm{.}78$ m below the second.