Q11 The velocity distribution in the flow of a thin film of oil down an inclined channel is given by (d v) sin | 2 = velocity where d = depth of flow, a = angle of inclination of the channel to the horizontal, u = at a depth y below the free surface, g = unit weight of oil and m = dynamic viscosity of oil. Calculate the shear stress: (i) on the bottom of the channel, (ii) at mid-depth, and (iii) at the free surface %3D