Relative Centrifugal Force. RCF is not strictly a force but rather the proportionality constant. When a centrifuge is used to enhance sedimentation or creaming, the square of the angular velocity times the distance of the dispersed species from the axis of rotation, when divided by the gravitational constant, g, yields the relative centrifugal force. It is substituted for g in Stokes' law to yield a sedimentation expression for centrifuges. Because RCF is expressed in multiples of g, it is also termed g-force or simply g's.