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Old 06-26-2006, 10:52 PM
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ThinkingPlus ThinkingPlus is offline
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Join Date: Sep 2005
Location: Palmdale, CA
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Rotating Reference Frames
Originally Posted by golf_sceptic
The words centripetal and centrifugal in physics have their dictionary meanings. centripetal=toward the centre, centrifugal=away from the centre. They are equal and opposite, action and reaction.

Most people get it wrong because they do not understand that the centripetal force acts on the stone, and the centrifugal force acts on the string (or the boy). We then get incorrect statements about the centrifugal force throwing the rock out and keeping the string taut and that sort of thing.

What keeps the string taut? The boy pulling on it.
What balances the centripetal force on the stone? Nothing, that's why it moves in a circle.

As a general rule, the more words used to describe the phenomenon,
the more errors will be introduced.
Centrifugal force is a convenient term describing an effective force present on objects in a rotating reference frame (an object undergoing centripetal acceleration). It is what our bodies, arms, and hands "feel" as the pulling away from the center of rotation during a swing. This concept and feel can be used as an aid to creating angular velocity. That is all that is claimed within TGM to my knowledge. Angular velocity and acceleration is what ultimately matters.
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