A centrifuge that is $40 \mathrm{~cm}$ ID and $30 \mathrm{~cm}$ long has an overflow weir that is $5 \mathrm{~cm}$ wide. The centrifuge operates at a speed of $3600 \mathrm{rpm}$.

(a) What is the maximum capacity of the centrifuge (in gpm) for which particles with a diameter of $25 \mu \mathrm{m}$ and $S G=1.4$ can be separated from the suspension?

(b) What would be the diameter of a settling tank that would do the same job?

(c) If the centrifuge ID was $30 \mathrm{~cm}$, how fast would it have to rotate to do the same job, everything else being equal?