The Myth of Centrifugal Force

We all know that centrifugal force exists don’t we?   It’s the outward force on an object traveling in a circle.  Pretty hard to deny it exists when we’ve all felt it every time we go around a tight turn in a car.

Except it really doesn’t exist, and you can prove it to yourself.  Take a small object and tie a string to it.  Then swing it in a circle (hey if you’re actually going to do this don’t go berserk and hurt someone or yourself).  Now that you have the object swinging around in a circle, ask yourself this question; are you pushing on the string or pulling on it?  You are pulling on it of course, you can’t push something around through a string.  What happens when you suddenly let go (safety precautions again of course, and if you break a window or hit someone I am not responsible).  As soon as you stop pulling on the string (applying an inward, not outward force) the object will fly off in a straight line.  No more force inward, no more going in a circle.

But the fact is it feels like there is an outward force when the car goes around a tight corner.  What is actually happening is that your body has momentum and is trying to go in a straight line.  What you are feeling is your momentum as the car starts to move sideways underneath you.  You’re not being thrown up against the side of the car.  The side of the car is moving over and pushing on you to make you go in a circle too.  The force it applies is called centripetal force.