Physics Help Forum Is centripetal force opposite but equal in magnitude of centrifugal force?

 Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

 Jul 23rd 2014, 06:24 PM #1 Junior Member   Join Date: Jun 2014 Posts: 22 Is centripetal force opposite but equal in magnitude of centrifugal force? Is centripetal force and centrifugal force action reaction pairs? If centrifugal force is not an action reaction pair with centripetal force, does centripetal force due to friction, gravity, and tension all have an action reaction pair? Sincerely, Jonathan
Jul 24th 2014, 02:23 AM   #2

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 Originally Posted by jlyu002 Is centripetal force and centrifugal force action reaction pairs? If centrifugal force is not an action reaction pair with centripetal force, does centripetal force due to friction, gravity, and tension all have an action reaction pair? Sincerely, Jonathan
The centripetal force is actually a net force: The sum of all the forces on an object that is pointed toward the center of the circle is equal to the centripetal force. As such it does not always have a Third Law reaction pair. In the circumstances when the object only has only one radial force on it, the typical Third Law pair might be friction (on the person in a seat) or the normal force.

The centrifugal force is not a force as such, it's related to the frame of motion you are looking at the problem in, but in the coordinate frames where it applies it is not a Third Law pair to the centripetal force. As I recall the centripetal and centrifugal forces do tend to be equal an opposite...just not Third Law pairs.

-Dan
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 Jul 24th 2014, 05:17 PM #3 Junior Member   Join Date: Jun 2014 Posts: 22 Thank you Dan! This clarified a lot. -Jonathan

 Tags centrifugal, centripetal, equal, force, magnitude, opposite