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Centrifugal force
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A fictitious outward force in a rotating frame.
F = mω²rIn a rotating frame a body appears pushed outward with fictitious force mω²r. In the inertial frame there is no such force; the body simply tends to go straight.
Mud flies off a wheel because there's not enough force to keep it in a circle.
Don't draw centrifugal force in an inertial-frame diagram together with the centripetal force.
In more detail
Centrifugal force is a fictitious outward force felt in a rotating frame. It is not a real force acting on the object, but it explains the sensation of being pushed outward.
Real-world uses
- Spin dryers remove water by using the outward effect of rotation.
- Centrifuges separate blood components using high rotational speed.
- Passengers on a spinning fairground ride feel pushed outward, which is the centrifugal effect in the rotating frame.
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Frequently asked questions
Is centrifugal force real?
It is not a real interaction. In an inertial frame, the object simply moves in a straight line if no inward force acts.
Why do I feel pushed outward on a roundabout?
Because your body tends to continue straight, while the car turns, so the seat pushes you inward and you feel pushed outward.
Is centrifugal force a real force?
It is a fictitious force that appears only in a rotating frame. In an inertial frame, the body simply moves in a circle under a real inward force.
Related topics in Newton's Laws & Forces
Conical pendulum · Vertical circular motion · Loop-the-loop · Pseudo forces · Drag force · Stokes' law