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Homework Help: Momentum ballistics speed question

  1. Oct 30, 2007 #1


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    In a ballistics test, a 25.0 g bullet traveling horizontally at 1100 m/s goes through a 30.0 cm-thick 450 kg stationary target and emerges with a speed of 900 m/s. The target is free to slide on a smooth horizontal surface.

    How long is the bullet in the target?
    i tried to use this equation : t = d/v_avg

    900-1100 / 2 = -100 = vavg
    .3=-100 t
    t= .003
    but it is saying that it is incorrect. can someone tell me what i am doing wrong?
  2. jcsd
  3. Oct 30, 2007 #2


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    Homework Helper

    Using kinematic formula can you find the retardation produced in the block?
    Last edited: Oct 31, 2007
  4. Oct 30, 2007 #3


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    um i guess not then...
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