Consider fully developed laminar flow of water in the annular space formed by the two concentric cylinders shown in the diagram for Problem $4,$ but with pressure gradient $\backslash$frac$\{\backslash$delta p$\}\{\backslash$delta x$\}=19\mathrm{.}7$ Pa$/$m $.$ Both cylinders are stationary ro$=2$cm$,$ ri $=1$cm$,$ viscosity of the water u $=0\mathrm{.}001$N$*$s$/$m$2$

$($a$)$ Find out value of u$($r$)$ in the middle of the annulus $($r $=\backslash$frac$\{$ro$+$ri$\}\{2\}$

with a unit of m$/$s$.$