Why The Centrifugal Force Is Not Real, According To Physicists

The centrifugal force is pretty cool. It could be used one day to create artificial gravity onboard space stations (saving sci-fi films a lot of budget in the process), sparing astronauts the strange effects of microgravity on their bodies. It is also responsible for the fact that the Earth bulges in the middle, and as a result, the fact that you weigh slightly less at the equator. But as any physics undergraduate will tell you, probably with quite a stressed-out look on their face, it isn’t a real force.

What do we mean by that? Well, say when you are on a roundabout spinning around, despite the fact that you feel yourself being “pushed” outwards, there is no external force pushing you off the play equipment. What you are actually feeling is the result of your own inertia, or the tendency for objects in motion to remain in motion in a straight line at the same velocity unless another force acts upon it.

An easy way to see this intuitively is to send balls rotating around a circle, then quickly releasing them and watching what direction they travel in.

From within your rotating frame of reference, it may feel like a real force, but outside of it, it is easier to see what is going on. 

As you swerve the wheels of your car, with the friction between your tires and the road creating an apparent “centripetal force”, your body – happily moving forward in a state of inertia – continues to try to move forward. From inside, it feels like you are being pushed by a force, but you are actually trying to carry on a straightforward path while your car swings a big donut.

All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.

An earlier version of this article was published in December 2023.

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