A liquid $(,)$ flows $($laminar$,$ steady & incompressible$)$ down a wide plane surface inclined by angle

$$ from horizontal. After an initial developing flow region, the depth of the liquid becomes constant

at $h$ on the plate. Show that the pressure within the fluid in the fully developed region is a function

of $y$ alone, and is given by the hydrostatic pressure distribution with $g$ replaced by gcos$.$

Obtain the velocity distribution and the volumetric flow rate per unit width.