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Homework Help: Bullet in wood

  1. Sep 11, 2006 #1
    Ok, so here's my question:

    A .22 rifle bullet, traveling at 350 m/s, strikes a block of soft wood, which it penetrates to a depth of 0.130 m. The block of wood is clamped in place and doesn't move. The mass of the bullet is 1.80 g. Assume a constant retarding force.

    I know this has already been posted in another thread, but i have an additional question that i can't get.
    1. How much time is required for the bullet to stop?
    i tried 0.130m/350m/s and got .00037143 seconds as an answer. This was not correct. Any suggestions on what to do?

    I already know that the wood exerts 848 N on the bullet
     
  2. jcsd
  3. Sep 11, 2006 #2
    F=ma where F=net force on the bullet=848N and m=mass of the bullet=.0018kg. Find a

    Vf=Vi+a*t
    Vf, Vi and a are all known at this point. Solve for time.

    Your answer is close. You are off by a factor of 2.
     
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