Q2: When the density difference between spherical" pigment particles and the vehicle in which the pigment is suspended is 2 g/cm, (a) what is the approximate particle radius at which settling of the pigment in the suspension can be observed? (b) ignoring Brownian motion effects, how much time would it take for a particle with a radius of 0.02 microns to settle a distance of 1 cm in a vehicle with a viscosity of 1 poise? (T. Patton, problem, 27.1) Given: 13 r(in u=0.02 20 barnv=*(P-P.)g (Stokes law) Where: v = equilibrium velocity, rsradius of pigment particle, n = viscosity of the medium, pa density of sphere and pi = density of medium, g = gravitational constant. t = h/v and t = time for pigment particle to fall to a distance, h