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.
Last edited by golf_sceptic : 06-26-2006 at 09:33 PM.
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