# Is there jerk on Uniform Circular Motion?

Jerk is the change in acceleration. If acceleration is changing, then there is jerk. Since there is a changing acceleration in circular motion, there is jerk in circular motion.

I'm not entirely sure what you mean by "manifest" though. It's simply something that can be measured.

As other answers and comments said, yes there is jerk. But it doesn't mean what you think. In everyday use, a jerk is a sudden acceleration, like a sudden yank on a rope. That is not what centripetal acceleration is like.

If you tie a rope to a rock and swing it around your head, you must pull on the rope to keep it moving in a circle. That is centripetal force and centripetal acceleration. If the rock is circling at a constant radius and speed, the magnitude of the force does not change. The direction smoothly changes. You have to keep pulling toward yourself as the rock moves around you.

The other answers about jerk, snap, crackle, and pop are apparently technical terms for higher derivatives of velocity. Though I had never heard of them before this question. They are not in common use. And these technical definitions do not imply sudden accelerations either.

Jerk is the derivative of acceleration. It is a semi-good name. It makes more sense to apply it to the derivative of force than acceleration.

Suppose you are pulling with constant force on a rope, trying to move a stuck object. You give the rope a yank. The force momentarily rises and then returns to its former value. The derivative of force reasonably fits the idea of jerking the rope, even if the object is still stuck. If the object breaks free and there is a non-zero acceleration, then the derivative of acceleration also reasonably fits the idea.

Jerk is a non-zero vector in uniform circular motion. But the motion does not fit the everyday idea of jerking the rope.