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Physics problem

  1. Oct 24, 2012 #1
    I shoot a bullet of mass m with velocity v against a block of mass M.
    Find how far the bullet penetrates the block. This problem turned up in my friends examination and I believe it can't be done without the coefficient of friction. Am I right or can this be calculated using conservation of momentum. If so please show me how.
  2. jcsd
  3. Oct 24, 2012 #2

    Doc Al

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    Staff: Mentor

    You're right: Not enough information is given. (Is that the full problem statement?)
  4. Oct 24, 2012 #3


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    I think there are some variables missing:
    Do you want the depth of the impact, or the length the block travels afterwards?
    Is the big block part of a pendulum? (very common problem, needs length of pendulum)
    Does the big block slide on a surface? (quite common problem, needs coefficient of friction)
    Last edited: Oct 24, 2012
  5. Oct 24, 2012 #4
    A resistance force is needed to solve the problem inside the block.
  6. Oct 24, 2012 #5
    No, I guess he didn't give me the entire question
  7. Oct 24, 2012 #6
    I'm guessing he couldn't do it because he didn't read it properly.
  8. Oct 24, 2012 #7
    Maybe. I need to ask him for his question paper
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