$($a$)$ What is the force required to move the moving sheet at a speed $V,$ as shown in the figure. Put down the answer $($without derivation$)$ in terms of fluid density $,$ viscosity $,$ distance $h,V,$ and surface area $A$ of the moving sheet.

$($b$)$ If the sheet is vertically displaced upward and its distance from the top wall is $\frac{h}{2}$ while the force is maintained, what will be the speed of the moving sheet?

$(1)0\mathrm{.}5$ V

$(2)1\mathrm{.}5$ V

$(3)0\mathrm{.}6$ V

$(4)$ V