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Homework Help: Hammer and Nail

  1. Feb 17, 2006 #1
    Hi! Here's the question: I really need a starting block for this because I really don't know where to start.

    The collision between a hammer and a nail can be considered to be approximately elastic. Estimate the kinetic energy acquired by a 15 g nail when it is struck by a 550 g hammer moving with a speed of 3.7 m/s.

    Do I use this equation: (M1 * Vo) = (M1 * V1Final) + (M2 * V2Final)

    My book doesn't help anymore than this! Please help!
  2. jcsd
  3. Feb 17, 2006 #2

    What does it mean fopr a collision to be elastic? There is one more concept that you need to use.
  4. Feb 17, 2006 #3
    Ok. I got it. I came up with this formula that substitutes the inelastic equation because like you said, there is more than once concept. Here is what I used:

    Kf = .5(m2) * (2m1 / m1 +m2)^2 * vo^2

    m2 is the weight of the nail in kg
    m1 is the the weight of the hammer in kg

    I got K= .3933 J

    Thanks for the help!
  5. Feb 17, 2006 #4
    The problem said the collision was elastic not inelastic and you definitely can't use conservation of energy with inelastic collisions.
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