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Homework Help: Angular velocity of suspended rod

  1. Jun 26, 2016 #1
    1. The problem statement, all variables and given/known data
    A uniform rod of length L & mass m is suspended through an end. It is shifted through an angle of π/2 radian i.e. made horizontal and then released. Find angular velocity when rod is vertical.

    2. Relevant equations

    3. The attempt at a solution
    My attempt to a problem is attached
    with this post.


    Solution says
    By energy conservation law
    1/2 I ω2= mg L/2
    (ω = angular velocity)
    ω=√ (3g/L)

    Which one is correct? N why other is wrong?

    Attached Files:

  2. jcsd
  3. Jun 26, 2016 #2
    but in your soln you have assumed that torque remains constant throughout which is wrong
    You must correct it and integerate to get the right answer
  4. Jun 26, 2016 #3
    Nope...i ve found the torque acting on the rod when it is in hzt position only.... and hence angular acceleration (alpha) also changes with theta...so by putting theta =π/2 i ve found w
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