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Rotational Motion . Chapter 7 & 8. Centripetal Force. Newton’s 2 nd Law Whenever there is acceleration there is a force to cause it F = ma F c = ma c. WARNING!!!. Centripetal Force is not a new, separate force created by nature! Some other force creates centripetal force
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Rotational Motion Chapter 7 & 8
Centripetal Force • Newton’s 2nd Law • Whenever there is acceleration there is a force to cause it • F = ma • Fc = mac
WARNING!!! • Centripetal Force is not a new, separate force created by nature! • Some other force creates centripetal force • Swinging something from a string tension • Satellite in orbit gravity • Car going around curve friction
Conceptual Problem • What affects Fc more: a change in mass, a change in radius, or a change in speed? • A change in speed since it is squared and the others aren’t.
Vertical Circular Motion Your Fc is your net force
Conceptual Example • During a circus trapeze act, a man hangs from a bar and swings his partner from their arms. Which is harder to do: hold the partner still under the bar, or to swing the partner under the bar? • Swing because not only is there gravity, but there is also centripetal force. • What provides the Fc? • Tension their arms