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Homework Help: Elastic Potential Energy and Energy Exchange

  1. Jan 15, 2012 #1
    1. The problem statement, all variables and given/known data

    A 3 kg ball is dropped from a height of 0.8 m above the top of the spring onto a vertical coiled spring sitting on the floor. The spring constant of the spring is 1200 N/m. Determine the maximum compression of the spring as the ball comes momentarily to rest before rising again. (0.22 m)

    2. Relevant equations
    1/2kx^2 (Spring Potential Energy as the area of kx graph)
    Epg=mgh (Gravitational Potential Energy)
    1/2mv^2 (Sum of energy -> Average kinetic energy of all particles -> velocity)

    3. The attempt at a solution

    I am not sure where I went wrong.
    I meant b=-29.43.
    x = 0.04905m
  2. jcsd
  3. Jan 15, 2012 #2


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    Homework Helper

    Decide from where do you count the height of the ball. If it is the upper end of the spring in equilibrium, then the final height is h2=x2 (a negative quantity).

  4. Jan 15, 2012 #3
    Nevermind, I figured it out. It makes more sense for the gravitational energy h2 to be down upwards to the ball.

    The first statement I made was false.

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