Centripetal Force Versus Centrifugal Force

Both centripetal and centrifugal force have identical magnitude, $m\omega^2r=\dfrac{mv^2}{r}$, but represent fundamentally different physical descriptions of the same circular motion, depending purely on which reference frame (inertial or rotating) the observer uses to analyse it (see Table 3.4 for the full comparison).

• Nature: centripetal force is real, from an actual physical interaction (tension, gravity, friction, normal force, etc.); centrifugal force is a pseudo (fictitious) force, with no physical source.
• Frame of validity: centripetal force acts in both inertial and non-inertial frames; centrifugal force appears only in rotating (non-inertial) frames.
• Direction: centripetal force points inward, toward the centre; centrifugal force appears to point outward, away from the centre.
• Origin: centripetal force arises from an interaction between two objects; centrifugal force arises purely from the object's own inertia, reinterpreted from a rotating frame.
• Effects: both are, in their respective valid frames, associated with real, observable physical effects. …