Centripetal force is needed to make something move in a circle. The force could actually be a number of things such as: friction, gravity, tension in a rope or any combination. Centripetal force is a name for a real force that has the role of making something move in a circle. This force is always directed towards the center of the circle of motion.

Centrifugal force is a virtual force.  It’s not really a force.  There are some situations you can be in that have you accelerating without speeding up.  One of these is a carnival ride that spins around in a circle at a constant speed. You feel pressed against the wall very tightly, and then the floor drops out.  Most people would believe they were moving steadily, with their bodies being pressed tightly against the wall (outward, in a centrifugal direction). This is centripetal force.  This isn’t really what happens.

When moving fast, a great deal of force is required to make you change direction. Your body “wants” to continue in a straight line. The curved wall gets in the way.  The wall pushes in against your body.  The “outward force” is just your body trying to move in a straight line.  It’s not a force at all. It’s inertia, your body resisting the effects of the forces it feels.


  • On February 15, 2018