The shear stress at a point 15 cm from the boundary is

Question

The equation of a velocity distribution over a plate is given by u = 2y- y² where u is the velocity in m/s at a point y meter from the plate measured perpendicularly. Assuming $\mu$ = 8.60 poise, the shear stress at a point 15 cm from the boundary is

a. 1.72 N/m²                     b. 1.46 N/m²

c. 14.62 N/m²                   d. 17.20 N/m²