C4.2 A belt moves upward at velocity V, dragging a film of viscous liquid of thickness h, as in Fig. C4.2. Near the belt,the film moves upward due to no

slip. At its outer edge, the film moves downward due to gravity. Assuming that the only nonzero velocity is v(x), with zero shear stress at the outer film edge, derive a formula for (a) V(x), (b) the average velocity Vavg in the film, and (c) the velocity V. for which there is no net flow either up or down. (d) SketchV(x) for case (c).