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!

SHM of a pendulum

  1. May 1, 2014 #1
    1. The problem statement, all variables and given/known data
    A uniform steel bar swings from a pivot at one end with a period of 1.2 seconds. How long is the bar?

    2. Relevant equations

    3. The attempt at a solution
    I manipulated this equation to solve for L, giving me L=[itex]T^{2}g/4\pi^{2}[/itex]
    Plugged in T=1.2 seconds and g=9.8. Answer I got was (to two significant figures) 0.36 m. But apparently that answer is wrong so I don't know what I am missing or if I am using the wrong equation.
  2. jcsd
  3. May 1, 2014 #2

    Doc Al

    User Avatar

    Staff: Mentor

    The equation you are using is for a simple pendulum, where all the mass is concentrated at the end. When the mass is spread out, as in your problem, you have what is called a physical pendulum, so you'll need to modify that formula a bit. Read this: Physical Pendulum
  4. May 1, 2014 #3
    That clears things up a bit. I got the answer now. Thanks.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: SHM of a pendulum
  1. SHM of Pendulum (Replies: 5)

  2. Pendulums and SHM (Replies: 7)