Chapter 10, Problem 84PP

Centrifuges are widely used in biology and medicine to separate cells and other particles from liquid suspensions. Figure 10.33 shows top and side views of two centrifuge designs. In both designs, the round holes are for tubes holding samples to be separated; the side views show two tubes in place. The total mass and radius of the rotating structure are the same for both, the sample-hole tubes are at the same radius, and the sample tubes are identical.

FIGURE 10.33 Two centrifuge designs, shown from the top and the side (Passage Problems 80-84).

If a centrifuge’s radius and mass are both doubled without otherwise changing the design, its rotational inertia will

1. a. double.
2. b. quadruple.
3. c. increase by a factor of 8.
4. d. increase by a factor of 16.