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Homework Help: Angular Momentum Equation

  1. Nov 8, 2008 #1
    1. The problem statement, all variables and given/known data
    A projectile of mass m moves to the right with a speed vi. The projectile strikes and sticks to the end of a stationary rod of mass M, of length d, that is pivoted about a frictionless axle through its center.

    p11-54.gif

    (a) Find the angular speed of the system right after the collision. (Use v_i for vi, m, M, and d as appropriate in your equation.)
    (b) Determine the fractional loss in mechanical energy due to the collision. (Use v_i for vi, m, M, and d as appropriate in your equation.)

    2. Relevant equations

    If[tex]\omega[/tex]f=Ii[tex]\omega[/tex]i
    W= K1-K2

    3. The attempt at a solution
    http://qaboard.cramster.com/Answer-Board/Image/2007111219463329548144409250092.jpg [Broken]
    i did it like this but for some reason my part (b) is saying that I'm wrong. Can someone help?
     

    Attached Files:

    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Nov 9, 2008 #2
    It all looks fine, but question (b) asks about the *fractional* energy loss, so you should divide your final answer by mv^2/2.
     
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