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Homework Help: Conservation of energy II

  1. Mar 13, 2007 #1
    A block of mass 0.08 kg is pushed against a spring with spring constant k=31 N/m. The srping is compressed 0.15 meters from its natural length. The block is released and it slides along a surface with coefficient of frition 0.45. How far does the block travel from the point at which is is released?

    I am having a problem developing an equation for this. It seems i am always short on something.

    this is what i have so far

    Work due to friction - work due to spring = work due to spring - work due to friction.

    I know i am missing something but i don't know what it is.
  2. jcsd
  3. Mar 13, 2007 #2
    Assume it is all horizontal. You have an initial set of numbers to calculate the force along the x axis and the frictional forces, Soecifty these, and we can help more.
  4. Mar 13, 2007 #3
    is my equation right or wrong
  5. Mar 13, 2007 #4


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    Gold Member

    Your equation says

    1 = -1

    Forget the spring and think about what happens if you just push the block with force f for 1 cm. Then return to the spring ...
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