The distribution of the x-component of the velocity u of a fluid near a flat surface is measured as a function of the distance y from the surface: u(y) y (m) 0.002 0.004 0.006 0.008 Try x u (m/s) 0.005 0.008 0.017 0.022 The shear stress t, in the fluid is described by Newton's equation: where u is the coefficient of dynamic viscosity. The viscosity can be thought of as a measure of the inter- nal friction within the fluid. Fluids that obey Newton's constitutive equation are called Newtonian fluids. Calculate the shear stress at y = 0 using (i) the two-point forward, and (ii) the three-point forward approx- imations for the derivative. Take u= 0.00516 N-s/m?.