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Old 12-21-2008, 01:44 PM
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Yoda Yoda is offline
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One Last Time . . .
Originally Posted by Jeff View Post

Yoda -

You asked-: "Assume a tethered ball in orbit around an axis. Does the tether (and its tension) serve as the centripetal force of that action? . . ."

I do not think that the tether (and its tension) of the tethered ball in orbit represents as the centripetal force.

. . .

The string . . . is not a source of the centripetal force. It is only the conduit whereby the centripetal force (the force that keeps the orbiting ball traveling in a circle) is transmitted from the hand to the ball.

[Bold emphasis by Yoda.]
Jeff,

As you know (and I know you do because you have so written elsewhere in this thread), centripetal force operates inward and not outward. In this instance, that means inward from the ball to the hand and not -- as you inexplicably state -- outward from the hand to the ball. This is why I earlier said (post #160) that you first acknowledge Newton's laws and then proceed to distort them to your own ends. In your post #169, you said that you "resent" that assessment, but your quote above is indisputable evidence of its truth.

For the rest of us, the object acting on the ball to cause this phenomenon is the string. Hence, the string supplies the centripetal force and not the hand. From my post #154:
We are concerned here with a mass orbiting about an axis of rotation and exhibiting both a centripetal force (a force 'seeking the center' and whose origin we are now debating) and a centrifugal force (a force 'fleeing the center' and that is reactive to the centripetal force). An orbiting mass constantly accelerates towards its axis of rotation. This centripetal acceleration demands an equal and opposite force that opposes the centripetal force and creates an outward centrifugal reaction directed away from the axis.

In your model, the ball is the orbiting mass and the hand is the axis of rotation. The hand is not the centripetal force (as you incorrectly state). It is, after all, the axis! Instead, the centripetal force (acceleration) is exerted on the ball by another object (in your model, the string). Then, the centrifugal reaction is exerted by the ball on the object that originated the centripetal acceleration (the string).
Until you accept the above, you contradict conventional scientific wisdom that has been in place for more than three centuries. Hence, there is no use in further exploring these ideas as they relate to the Golf Stroke.
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