A hollow steel sphere, 5 mm in diameter with a mass of 0.05 g, is released in a column of liquid and attains an upward terminal velocity of 0.005 m/s. The liquid density is 900 kg/m³, and the sphere is far enough from the container walls so that their effect may be neglected. Determine the viscosity of the liquid in kg/m s. Hint: Assume Stokes flow and confirm the assumption with your answer.