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Homework Help: Collision around a pendulum

  1. Mar 17, 2009 #1
    1. The problem statement, all variables and given/known data
    A pendulum consists of a mass M hanging at the bottom end of a massless rod of length l, which has a frictionless pivot at its top end. A mass m, moving as shown in the figure with velocity v impacts M and becomes embedded.

    What is the smallest value of v sufficient to cause the pendulum (with embedded mass m) to swing clear over the top of its arc?

    2. Relevant equations


    3. The attempt at a solution
    I realize that the acceleration must be [tex]\frac{v^2}{l}=g[/tex] to swing over the arc. Thus, I found:

    [tex]v_f=mv_i/(m+M)[/tex], and set Vf equal to [tex]\sqrt{lg}[/tex] from the first equation.

    I got:

    But the software returned:
    Code (Text):
    Your answer either contains an incorrect numerical multiplier or is missing one.
  2. jcsd
  3. Mar 17, 2009 #2


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    Homework Helper

    What is the top of its arc?

    Is there a figure you can provide or describe in better detail?
  4. Mar 17, 2009 #3
    Sure. See the attachment.

    Attached Files:

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