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Box with mass attached to spring and board

  1. Oct 13, 2008 #1
    1. The problem statement, all variables and given/known data

    A 0.580Kg wood block is firmly attached to a very light horizontal spring. It is noted that the block-spring system (k=160N/m), when compressed 4.0cm and released, stretches out 0.9 cm beyond the equilibrium position before stopping and turning back.

    2. Relevant equations

    Conservation of Mechanical Energy




    3. The attempt at a solution

    Ok, What I tried to do is solve for the work of friction using

    (coefficient of friction)(Normal Force)(d)=1/2k(xf-xi)^2. However, I do not understand what the problem is asking as far as distances. I converted the distance to m but I still do not know what they mean by compressed for 4 cm. Does that mean they pushed it 4 cm forward. Let it go and it went past its resting point .9 cm. If so is .9 negative? or is 4 cm negative?
  2. jcsd
  3. Oct 13, 2008 #2


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    Staff Emeritus
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    Gold Member

    That would be correct.

    However, you have failed to state what the question is asking you to find.
  4. Oct 13, 2008 #3
    what im looking for is the coefficient of friction.
  5. Oct 13, 2008 #4


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    Staff Emeritus
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    Ahh right. Looking back at the question, is doesn't matter which (extension/compression) you choose as positive and which you choose as negative provided that one is positive and one is negative.

    Your approach is correct by the way.
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