Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Please explain centripetal acceleration?

  1. Oct 23, 2007 #1
    can some1 please explain centripical accleration? i dont get it at all
  2. jcsd
  3. Oct 23, 2007 #2
    It is the acceleration a body feels when following a circular trajectory, towards the centre of that circle.

    Imagine modelling the a particle's position as:
    [tex]x = r \cos \omega t[/tex] and [tex]y = r \sin \omega t[/tex]
    This is simply circular motion at a radius r.

    By differentiating twice you find the acceleration:
    [tex] {\partial^2 x} / {\partial t^2} = - \omega^2 r \cos \omega t[/tex] and [tex] {\partial^2 y} / {\partial t^2} = - \omega^2 r \sin \omega t[/tex]

    Which is a vector that points towards the centre of the circle, this is centripetal acceleration.

    Does this help?? :P

  4. Oct 23, 2007 #3


    User Avatar
    Gold Member

    This isn't a rigourous explanation but I hope it helps; here goes:

    If an object is moving in a circular motion with a constant speed we refer to the motion as being uniform circular motion. Now if we take the velocity at any instant i.e the instantaneous velocity, we find that in order for the object to maintain its circular motion the direction in which it is travelling is ALWAYS tangential to the circle. For this reason, the velocity is NEVER constant, and there is no component of acceleration parallel to the path at any instant because if this was the case the speed would increase. So for the speed to remain constant the acceleration must ALWAYS be in the direction perpendicular to the instantaneous velocity i.e towards the centre of the cirlce.
    Last edited: Oct 23, 2007
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook