Centripetal Force Is a Role, Not a New Force

Every object moving in a circle needs a net force pointing toward the center of that circle. Newton's second law demands it, since curving is accelerating, and acceleration needs a cause. But 'centripetal' doesn't name a new physical force sitting alongside gravity, friction, and tension. It's a role. Something has to play that role, and your job is to find out which real force is doing the work in each situation. A car turning a corner needs an inward push, and the only horizontal force available is friction between the tires and the road, so friction takes the job. A ball on a string needs an inward pull, and tension provides it. A satellite needs an inward pull too, and gravity provides it.

To identify the centripetal force in any setup, draw the free-body diagram like always, then ask which of those forces, or which component of them, points toward the center of the circular path. Add up the components pointing inward, set that sum equal to mv²/r, and solve. There is no separate arrow labeled 'centripetal' to draw. If you draw one, you've double-counted.

This connects directly to the misconception that riders on a spinning ride feel a centrifugal force flinging them outward. From the ground, there's no such force. The wall pushes the rider inward, and the rider's inertia, their tendency to keep moving straight, is what makes them feel pressed against the wall. The outward sensation is your body resisting the turn, not a real push.