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Magnitude of bullet fired into gel

  1. Feb 13, 2010 #1
    1. The problem statement, all variables and given/known data
    A rifle bullet with a muzzle speed of 330 m/s is fired directly into a special dense material that stops the bullet in 25.0 cm. Assuming the bullet's deceleration to be constant, what is its magnitude?

    V=330 m/s

    2. Relevant equations


    3. The attempt at a solution

    I don't fully understand the problem, to me it sounds like they want the magnitude of force exerted on the bullet in the opposite direction it was fired? I'm really confused.

  2. jcsd
  3. Feb 13, 2010 #2


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    No, they are looking for the magnitude of the bullet's acceleration (deceleration).
  4. Feb 13, 2010 #3
    The initial speed, u, is 330m/s, the final speed, v is 0 m/s since the bullet comes to rest. The bullet travels a distance, s of 0.25m.

    The equation of motion v^2=u^2 +2as should be of help.

    Note that this will give you a negative acceleration which is to be expected as it is opposing the direction of motion.
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