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Homework Help: Conversation of mechanical energy

  1. Mar 9, 2010 #1
    1. The problem statement, all variables and given/known data
    A 700 g block is released from rest at height h(not) above a vertical spring with spring constant k= 400 N/m and negligible mass. The block sticks to the spring and momentarily stops after compressing the spring 19.0 cm. How much work is done (a) by the block on the spring and (b) by the spring on the block? (c) What is the value of h(not)? (d) If the block were released from height 2.00h(not) above the spring, what would be the maximum compression of the spring?

    2. Relevant equations

    Work on block wb= -1/2 kx^2
    h(not)=-x +1/2 kx^2/mg
    to find x :kx^2 -2mgx - 4mgh(not) = 0

    3. The attempt at a solution
    a. i used work on block and got 7.22J
    b. would be opposit energy of work on block thus being -7.22J
    c.used h(not) and got 0.86 m
    then from finding x i used quadratic formul and got x=0.26 m
    d. do not know how to find2.00h(not)
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Mar 10, 2010 #2
    You seem to have answered problem d at the end of problem c. I think you need
    3 significant digits in your answer.
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