Editing Centripetal force (section)

== Sources ==
[[File:Centripetal force diagram.svg|thumb|A body experiencing [[uniform circular motion]] requires a centripetal force, towards the axis as shown, to maintain its circular path.]]
In the case of an object that is swinging around on the end of a rope in a horizontal plane, the centripetal force on the object is supplied by the tension of the rope. The rope example is an example involving a 'pull' force. The centripetal force can also be supplied as a 'push' force, such as in the case where the normal reaction of a wall supplies the centripetal force for a [[wall of death (motorcycle act)|wall of death]] or a [[Rotor (ride)|Rotor]] rider.

[[Isaac Newton|Newton]]'s idea of a centripetal force corresponds to what is nowadays referred to as a [[central force]]. When a [[satellite]] is in [[orbit]] around a [[planet]], gravity is considered to be a centripetal force even though in the case of eccentric orbits, the gravitational force is directed towards the focus, and not towards the instantaneous center of curvature.<ref>
{{cite book
| title = In Quest of the Universe
| edition = 6th
| author = Theo Koupelis
| publisher = Jones & Bartlett Learning
| year = 2010
| isbn = 978-0-7637-6858-4
| page = 83
| url = https://books.google.com/books?id=GVlpKZ67DscC&pg=PA83
}}</ref>

Another example of centripetal force arises in the helix that is traced out when a charged particle moves in a uniform [[magnetic field]] in the absence of other external forces. In this case, the magnetic force is the centripetal force that acts towards the helix axis.