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Physic question

  1. Dec 27, 2009 #1
    1. The problem statement, all variables and given/known data

    A soft clay block is suspended so as to form a so-called ballistic pendulum. A bullet is fired point-blank into the block, imbedding itself therein and raising the latter to a height h. Derive an expression for the percentage of the kinetic energy converted into internal energy during the bullet-clay impact.

    2. Relevant equations
    Use any equation related to momentum and kinetic energy

    3. The attempt at a solution
    I managed to get an expression: (mBvB2 - mBvC2 - mCVC2)/(mBvB2) x 100
    This expression is right, but I need to simplify it to (mC)/(mC + mB) x 100. I don't know how to simplify this equation
  2. jcsd
  3. Dec 27, 2009 #2


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    Homework Helper

    Use conservation of momentum and write VB in terms of VC. Substitute this in the energy equation to eliminate VC.
  4. Dec 27, 2009 #3
    Can you show me how to do that? I tried but had no luck
  5. Dec 27, 2009 #4


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    Homework Helper

    mBVB = (mB+mC)VC
    Now what is VB ?
  6. Dec 27, 2009 #5
    i got it! thanks
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