Question

a) Give the equation for terminal speed in the variables from Stoke's Law, and the densities of the sphere Ps and the fluid P1.

b) Find the viscosity of motor oil (in kg/m/s) in which a steel ball of radius 0.85mm falls with a terminal speed of 4.32cm/s. The densities of the ball and oil are 7.8 and 0.78 g/ml, respectively.