$6\mathrm{.}9\mathrm{.}11$ A viscous fluid $($specific gravity $=1280$ kg$/$m$3$ viscosity $=0\mathrm{.}02$ N$.$s$/)$ is between two infinite parallel plates, as shown in Figure P$6\mathrm{.}9\mathrm{.}11.$ The fluid moves between the plates by the action of a pressure gradient, and the upper plate moves at velocity U while the lower plate is fixed. The pressure gauge of the U$-$shaped pipe connected to the lower end of the two points shows a difference of $0\mathrm{.}003$ m$.$ If the upper plate is moving at a velocity of $0\mathrm{.}006$ m$/$s$,$ at what distance from the lower plate will the maximum velocity occur? However, laminar flow is assumed.