I have tried the differences of the velocities and distance (du/dy) . Then multiplied it by the dynamic viscosity which came out as 0.36 N/m^2 but the answer is apparently 1.17 N/m^2.
Homework Statement
If the velocity v of the air in a boundary layer having a dynamic viscosity of
18x10-6 kg/ms is given in terms of the distance y from the surface by v = ay + by2
where a and b are constants, calculate the surface shear stress if at 1.5 mm from the surface the velocity is 75...