Problem 5 A laminar flow occurs between two horizontal parallel plates under a constant pressure gradient dp/ds (p decreases in the positive s direction). The upper plate moves left (negative) at

velocity u. The expression for local velocity u is given as 1 dp 2μ ds (Hy- y²) + u₁ // U a. Is the magnitude of the shear stress greater at the moving plate (y-H) or at the stationary plate (y=0)? b. Derive an expression for the y position of zero shear stress. c. Derive an expression for the plate speed u, required to make the shear stress zero at y=0.