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Homework Help: Ballistics Pendulum

  1. Oct 14, 2008 #1
    1. The problem statement, all variables and given/known data

    A 23 g bullet traveling 235 m/s penetrates a 3.8 kg block of wood and emerges cleanly at 195 m/s.

    If the block is stationary on a frictionless surface when hit, how fast does it move after the bullet emerges?

    2. Relevant equations

    (1) mv= (m+M)v'

    momentum before= momentum after

    (2) 1/2(m+M)v'^2 = (m+M)gh
    3. The attempt at a solution

    I attempted to solvethis using these two equations and I received an answer for 1.14 m/s and 230 m/s. I am having a lot of trouble even determining how to start this problem. I dont want a quick easy answer but I would like help working through it! Thank You!
  2. jcsd
  3. Oct 15, 2008 #2


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    Science Advisor
    Homework Helper

    Hi 12boone! :smile:

    However did you use equation (2)? :confused:

    Equation (1) should be enough.

    Try again! :smile:
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