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: Hinged rod attached to elastic string

  1. Aug 13, 2012 #1
    A rod (mass M, length L) hinged at point X. End Y is attached to X by an elastic string passing over a pin P, the natural length of the string is L. P is a distance L from X.

    Elastic Modulus of string: (1/4Mg)

    Refer to GPE to X and prove that total PE is: (1/4)MgL(1-cosθ-2sinθ) and find angle θ for the equilibrium position.

    http://img155.imageshack.us/img155/1247/47349211.png [Broken]

    I literally have no idea where to begin with this and any help at all would be greatly appreciated.

    Thank you in advance.
     
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Aug 13, 2012 #2

    rude man

    User Avatar
    Homework Helper
    Gold Member

    How about summing torques about X to zero?

    And then maybe an apposite trigonometric identity?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook