The following turbulent-flow velocity data u(y), for air at 75°F and 1 atm near a smooth flat wall, were taken in the University of Rhode Island wind tunnel:
y, in: 0.025 0.035 0.047 0.055 0.065
u, ft/s: 51.2 54.2 56.8 57.6 59.1
Estimate (a) the wall shear stress and (b) the velocity u at y = 0.22 in.