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Homework Help: Conservation of angular momentum of pucks

  1. Nov 6, 2011 #1
    1. The problem statement, all variables and given/known data

    Two identical pucks, each of inertia m, are connected to a rod of
    length 2r and negligible inertia that is free to rotate about its center. A third puck of inertia m strikes one of the connected pucks perpendicular to the rod with a speed vi

    Write the expression for conservation of angular momentum in terms of m, vi, the
    final velocity of the puck, vf , and ω, the angular speed of the connected pucks. No I’s should be left. You do not need to solve these for vf and ω


    2. Relevant equations
    Well angular momentum is L=Iω
    I=(1/2)MR^2



    3. The attempt at a solution
    I have L=((1/2)MR^2)(ω)

    However I dont see where the Velocities should go
     
  2. jcsd
  3. Nov 6, 2011 #2

    Andrew Mason

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    Science Advisor
    Homework Helper

    I am not clear about the question. Is there a fixed pivot at the centre of the rod?

    AM
     
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