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: Central potential

  1. May 2, 2010 #1

    I am trying to compute the potential for a central force of the form: F(r) = f(r)r
    where r=|r|

    Using the conservative force information, equation1 comes for potential V(r):

    equation1: V(r) = [tex]\int [/tex] (-F(r))= [tex]\int [/tex] (-f(r) r)

    In http://en.wikipedia.org/wiki/Central_force" [Broken]it is stated that this integral is bounded from |r| to infinity. However I could not understand the reason.

    Could someone help me?
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. May 2, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hello mystraid! Welcome to PF! :wink:

    It has to be bounded from |r| to somewhere

    we can choose that somewhere to be anywhere, but it makes it simplest if we choose it to be ∞ (so the potential is always 0 at ∞). :smile:
  4. May 3, 2010 #3
    Thank you for the reply tiny-tim.

    And, I have another question. What if the function is dependent on the position vector r but not the magnitude of it?


    F(r) = f(r)r

    Then is there any potential for such a force, and if so, under what conditions it exists?

  5. May 3, 2010 #4


    User Avatar
    Science Advisor
    Homework Helper

    I'm sorry, I don't understand. :confused:
  6. May 3, 2010 #5
    Me, too:smile:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook