centrifugal force

Riders on a swing carousel interpret the cessation of upward motion as a balancing of the force of gravity, the force of the tension of the chains, and a centrifugal force pushing them away from the center of rotation. A stationary observer on the ground observes uniform circular motion, which requires a net centripetal force that is the combination of the force of gravity and the force of the tension of the chains.

In Newtonian mechanics, a centrifugal force is a kind of fictitious force (or inertial force) that appears to act on all objects when viewed in a rotating frame of reference. It appears to be directed perpendicularly from the axis of rotation of the frame. The magnitude of the centrifugal force F on an object of mass m at the perpendicular distance ρ from the axis of a rotating frame of reference with angular velocity ω is