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Homework Help: Mass dropped onto a spring.

  1. Nov 13, 2012 #1
    A 20-cm-tall spring with spring constant 5000 N/m is placed vertically on the ground. A 10.0 kg
    block is held 17.0 cm above the spring. The block is dropped, hits the spring, and compresses
    it. What is the height of the spring at the point of maximum compression?

    Here is what i did, i am just unsure if what i did is correct.

    PE=potential energy
    PE of the block initially(PEbi) = PE of the spring final(PEsf) + PE of the block final(PEbf)
    PEbi = PEsf + PEbf
    mghi = .5kx^2 + mghf
    x = sqrt[2(mghi-mghf)/k)
    in this case hf is equal to x
    plugging in the numbers i got x to equal 10.25cm
    where x is the height of the compressed srping
    Last edited: Nov 13, 2012
  2. jcsd
  3. Nov 13, 2012 #2
    As per the forum rules, you need to show us your attempt.
    For a start, try to form an equation using energy conservation.
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