1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Force on a massive ring

  1. Jul 21, 2011 #1
    1. The problem statement, all variables and given/known data
    A massive ring (radius = a and mass = M) lies on the xy plane. Calculate the force F on a test mass m at position z on the z axis.
    Now assume a = 1 and GMm/a2 = 1 in some system of units.

    (a) What is the force on m at z = 0?
    I got the answer for this its 0
    (b) What is the force on m at z = a?
    the answer for this is 0.354
    (c) What is the maximum force on m ?
    I am stuck on this one.


    2. Relevant equations

    F=(GMm)/r^2

    3. The attempt at a solution

    after some work I get F=(2GmMx)/(x^2+a^2)^3/2
    i know this is right because i got part b from it, however i dont Know how to find the maximum, my gut feeling is take the derivative with respect to x and set it equal to zero and then solve for x and plug back into F
     
  2. jcsd
  3. Jul 21, 2011 #2

    gneill

    User Avatar

    Staff: Mentor

    I'm not sure where that "2" comes from in your force expression. Better check that derivation.

    And yes, you need to differentiate and solve as you've outlined.
     
    Last edited: Jul 21, 2011
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Force on a massive ring
  1. 3 Forces on a Ring (Replies: 12)

Loading...