[Jeff]

Yoda - I have been deciding whether to respond to your last post. Your tone is demeaning and ill-conducive to an ongoing debate. Why can't you simply state your disagreements without pontificatiing, and implying that you are the final arbiter of the "truth"?

I don't think that you understand my perspective.

I will rephrase it.

The hand's movement is the source of energy that gets the ball to move in space. The string transmits that energy to the ball by means of a continuously taut string - any hand movement in a circular manner causes the ball to move in a circular manner (at the same rpm but along a wider circle of greater radius). The energy imparted to the ball gets the ball to perform two actions - i) acquire a surface speed of a finite value; and ii) centripetally accelerate - which merely represents a constant change in direction so that the ball follows a circular path.

The string is continously taut. That is necessary to counteract the tendency of the ball to fly away (due to centrifugal forces). Therefore, you are correct to state that the taut string represents the centripetal pull towards the center to counteract the tendency of the ball to fly away in a straight line direction at a tangent to the circle. However, the centripetal pull is not created by the string - the string is merely reactive to the dynamic situation of an orbiting ball that has acquired enough energy to fly away unless the string remains taut and provides a centripetal pull towards the center.

My personal perspective is focused on the following facts.

1) The source of energy for the orbiting ball is the continuous movement of the hand in a circular motion.
2) The hand constantly pulls the orbiting ball via a taut string - so that the orbiting ball revolves at the same rpm as the hand.
3) The ball acquires motional energy from the hand via the taut string, and this energy includes a centrifugal tendency which requires an equal counteracting centripetal pull by the taut string to ensure that the orbiting ball moves in a circular orbit.
4) It is true that the taut string is a constant reflection of the centripetal pull towards the center. However, the string doesn't independently create that centripetal force. The centripetal force only becomes necessarily operant because the ball has acquired motional energy from the motion of the hand that would cause it to fly off into space unless there was a centripetal pull from the taut string to counteract/equalize that centrifugal tendency.

Jeff.