4. Crude oil, with a specific gravity of 0.95 and a viscosity of µ = 3.15 N-s/m 2, flows steadily down a surface inclined at an angle of 0 = 45° below the horizontal. The thickness of the film is h = 0.5 cm. The velocity profile is given by = x - ہے۔ وہ ہے pg hy μ sin O 2 where p is the density of the oil. Coordinate x is along the surface and y is normal to the surface. A. Plot the velocity profile, and B. Determine the magnitude and direction of the shear stress x that acts on the surface.