You wish to capture particles with a 3 µm radius suspended in a fluid that has a linear density gradient with a density of 1.12 g/cm^3 at the bottom and 1.00 g/cm^3 at the top. you layer a thin particle suspension on the top of the 6 cm column of fluid with a viscosity of 1.0 cp and allow particles to settle.
a) how long must you wait for particles with a density of 1.07 g/cm^3 to sediment to within 0.1 cm of their isopycnic level (i. e., within 0.1 cm of the position where the density of the particles and the density of the fluid are equal)?
b) instead of settling due to gravity, you choose to use a centrifuge running at 800 rpm. if the top of the fluid is 5 cm from the center of rotation, how long must you run the centrifuge for the particles to move to within 0.1 cm of their isopycnic level?