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: Simple Harmonic Motion

  1. Sep 19, 2004 #1
    A cylindrical wooden log is loaded with lead at one end so it floats vertically in water. The submerged part is 2.56 m (called L). I'm supposed to show the oscillation is simple harmonic.

    Can someone point me in the right direction? For some reason I'm thinking gravity and density play a big part of find the this equation. After that, I can find the period.
  2. jcsd
  3. Sep 19, 2004 #2


    User Avatar
    Science Advisor
    Homework Helper

    Gravity pulls the log down and buoyancy pushes it up. The buoyant force is equal to the difference between the weight of the submerged portion of the log and water that would occupy the same volume. If you work these out correctly your equation of motion should look like a simple harmonic oscillator.
  4. Dec 2, 2004 #3
    how would you model this motion? How do you find w(omega). D

    Do you model this as a spring force on the object? I have a similar problem and am stuck. Thanks!
  5. Dec 2, 2004 #4
    The bouyant force goes like distance submerged. That will push it up, gravity will push it down. Work out the algrebra and get it into a form where you recognize.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook