A viscous fluid (specific weight $=80 \mathrm{lb} / \mathrm{ft}^{3} ;$ viscosity $\left.=0.03 \mathrm{lb} \cdot \mathrm{s} / \mathrm{ft}^{2}\right)$ is contained between two infinite, horizontal parallel plates as shown in Fig. P6.97. The fluid moves between the plates under the action of a pressure gradient, and the upper plate moves with a velocity $U$ while the bottom plate is fixed. A U-tube manometer connected between two points along the bottom indicates a differential reading of 0.1 in. If the upper plate moves with a velocity of $0.02 \mathrm{ft} / \mathrm{s}$, at what distance from the bottom plate does the maximum velocity in the gap between the two plates occur? Assume laminar flow.