This set of functions help to find the relative centrifugal force (g force) at a
give rpm for a rotor and also the rpm needed for a certain g force. The calculations
need the average radius of the rotor. This is normally stamped on the rotor, but
can be calculated by adding the distance from the centre of the spindle to the furthest
part of the centrifuge tube to the distance between the centre point and the nearest
point of the tube and then dividing by 2.

RPM to RCF

Revolutions per minute (RPM) Average radius of the rotor (cm)

RCF to RPM

Relative centrifugal force (g) Average radius of the rotor (cm)