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!

Homework Help: Period of Thick Ring

  1. Nov 10, 2008 #1
    I can't seem to make the necessary connections in this problem.

    Complete the algebra to show that the period for a thick ring ( the difference between the outer and inner radius is very large) is:

    T = 2π √[(d/g) + ((ΔR)^2/4Rg)]

    d= diameter of the ring


    Ro (outer radius)= R + ΔR/2
    Ri (inner radius) =R - ΔR/2

    I know that Icm(moment of inertia about the center of mass) = 1/2 M (Ro^2 + Ri^2)

    and for a thin ring where Ro & Ri are nearly identical, I=1/2MR^2

    Parallel Axis theorem: I total = Icm + MD^2

    T = 2π √(d/g) = 2π √(I/mgr) for a thin ring

    I tried to find I and substitute it into the equation 2π √(I/mgr), but I did not get the correct answer. Can anyone tell me what the key to this problem is?
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted