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Homework Help: Bullet fired into wooden block. Trying to find kinetic energy of bullet and block.

  1. Nov 7, 2008 #1
    Stuck on this one problem which states:
    A bullet with a mass of 6.00 g, traveling horizontally with a speed of 370 m/s, is fired into a wooden block with mass of 0.750 kg, initially at rest on a level surface. The bullet passes through the block and emerges with its speed reduced to 120 m/s. The block slides a distance of 49.0 cm along the surface from its initial position.
    Use g = 9.81 m/s^2 for the acceleration due to gravity.

    And I am trying to find this:
    What is the kinetic energy of the block at the instant after the bullet passes through it?

    If more information is needed, I can post it. Thanks in advance for your help.

    Btw, the first portion of the question asked for the coefficient of friction, which I was able to get:
    What is the coefficient of kinetic friction between block and surface?

    and this:
    What is the decrease in kinetic energy of the bullet?
    368 J
  2. jcsd
  3. Nov 7, 2008 #2


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    Staff Emeritus
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    Gold Member

    Re: Bullet fired into wooden block. Trying to find kinetic energy of bullet and bloc

    Can you find an expression for conservation of energy of the system?

    Of course we are ignoring any deformation of the block or bullet.
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