Repeat Prob. 15–99 by considering the more general form of Stokes law expressed as F_D = 3πμDV + (9π/16)ρV²D² where r is the fluid density.

Repeat prob.

During an experiment, three aluminum balls (ρ_s = 2600 kg/m³) having diameters 2, 4, and 10 mm, respectively, are dropped into a tank filled with glycerin at 22°C (ρ_f = 1274 kg/m³ and μ = 1 kg/m·s). The terminal settling velocities of the balls are measured to be 3.2, 12.8, and 60.4 mm/s, respectively. Compare these values with the velocities predicted by Stokes law for drag force F_D = 3πμDV, which is valid for very low Reynolds numbers (Re << 1). Determine the error involved for each case and assess the accuracy of Stokes law.