I am a university educated (primarily sciences), middle aged dude and I still cannot understand the difference between these 2 forces / phenomena.
In: Physics
Centrifugal force is the fictitious force caused by an object’s inertia. Objects in motion want to stay in motion in a straight line. When you spin something, you’re constantly making it curve away from the straight line. The inertia that’s trying to keep it going in that straight line is centrifugal force.
The path the object actually takes is a circle. The path inertia is trying to make it take is a straight line. [So, the inertial path is a tangent to the circle.](https://d138zd1ktt9iqe.cloudfront.net/media/seo_landing_files/prove-that-perpendicular-at-point-of-contact-to-tangent-to-a-circle-pass-01-1625468278.png) To make it go in a circle, you are constantly accelerating it towards the center of the circle. The apparent force caused by inertia is opposite to that, which means it’s directly *away* from the center, 90° to the tangent, or “down” from your perspective with the center of the circle being “up.”
Centripetal force is the very real force that’s causing it to go in a circle instead of in a straight line. Since the object’s inertia “wants” to go in a straight line, you must apply some kind of force to accelerate it away from that straight line. That force is centripetal force. If you’re spinning something attached to a string, the centripetal force is the intermolecular forces holding the string together. For a planet orbiting a star, it’s gravity.
So: object wants to go in a straight line. Centripetal force doesn’t let it. Centrifugal force is it trying to anyway.
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