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Homework Help: Two springs one trolley, find velocity

  1. Apr 11, 2013 #1
    1. The problem statement, all variables and given/known data

    Please refer to the image.

    My workings= pencil
    Answer= pen

    Why is my working wrong? What wrong assumptions did I make?

    2. Relevant equations

    Hooke's law/Newton's second law/ Elastic potential energy =0.5 kx^2

    3. The attempt at a solution
    As shown in the image.

    Attached Files:

  2. jcsd
  3. Apr 11, 2013 #2

    Doc Al

    User Avatar

    Staff: Mentor

    You used a kinematic formula for uniformly accelerated motion. That won't apply here, since the acceleration varies with displacement.

    Stick to energy conservation.

    What is the total spring PE at equilibrium?

    What is the total spring PE when the trolley is displaced?
  4. Apr 12, 2013 #3
    Got it, thank you.
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