A long ruler rests on a thin film of water on a table, as shown in figure Q2.1 below. A student tries to lift the ruler at speed W = h/Ot; adhesion causes the water to flow inwards. W Y B A h Figure Q2.1 Cross section of ruler on table. (a) Assuming that the pressure p varies with a only, show that the Navier-Stokes equations reduce to the equation dp dx State clearly all the assumptions made. = 1 dux dy2 (b) From this show that the velocity in the x-direction is given by Ux= 1 dp 2 dx (y - yh) (c) Use the equation of continuity to find an expression for Duty, and hence show that h dp ay W = 12 dx