Conservation of energy

Discussion in 'Physics' started by braddy, Oct 26, 2005.

  1. braddy

    Thread Starter Well-Known Member

    Dec 29, 2004
    83
    0
    Hi can someone help me with this problem:

    If a .75 kg block is rested on the top of a vertical string of force constant 45N/m, how much potential energy is stored in the spring relative to its equqilibrium configuration?

    I tried to use the conservation of energy , but it did not let me to a good conclusion.

    Thank you

    B
     
  2. n9352527

    AAC Fanatic!

    Oct 14, 2005
    1,198
    3
    The force exerted down by the block on the spring is

    F = mg

    The spring is compressed for a length of h due to this force

    h = F / force constant

    Energy stored is either the potential energy of the block

    E = mgh

    or the potential energy stored in the string

    E = Fh

    They are both equal.
     
  3. braddy

    Thread Starter Well-Known Member

    Dec 29, 2004
    83
    0
    thank you very much
     
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