[Jeff]

Here is another perspective on the orbiting ball situation.

I prefer not to even think of CP forces and/or CF forces.

I simply know that the hand moves in a small circle, and that the orbiting ball rotates in a larger circle, and that they rotate at the same rpm. I know that they are connected together by a piece of string. I know that the energy source is the hands (rotating in space). In that sense, the hands are pulling the ball via the string. I know that the orbiting ball follows a circular path because the hands follow a circular path, and that the string will remain taut if the hands move smoothly and at an even pace. I know that the whole system breaks down if the hands suddenly accelerate, or suddenly decelerate, or if the hands move in a straight line.

I don't need to invoke concepts of CP force or CF force to understand what is happening in this orbiting ball situation.

The same applies to the pivot. I don't need to think of a pivot center or a pivot axis. I simply think of how the body moves in 3-D space.

Jeff.