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Homework Help: Amplitude of oscillation?

  1. Nov 18, 2008 #1
    1. The problem statement, all variables and given/known data
    A 200 g ball attached to a spring with spring constant
    2.50 N/m oscillates horizontally on a frictionless table. Its velocity is 18.0 cm/s when x = -5.00 cm.
    A. What is the amplitude of oscillation?

    B. What is the speed of the ball when x = 3.00 cm?

    2. Relevant equations
    A. [tex]\omega[/tex] = sqrt k/m = sqrt 2.50/.200
    v(t) = A*[tex]\omega[/tex]*sin([tex]\omega[/tex]t)
    t = 0
    v(t) = A[tex]\omega[/tex]

    B. Vx2 = [tex]\omega[/tex]2(A2 - x2)

    3. The attempt at a solution
    I've tried several times to get a solution and I have never gotten the same answer twice...
    A. [tex]\omega[/tex] = 3.54
    A = 5.09 cm

    B. When x = 3.00 cm, V = 14. 56 cm.

    Neither of these answers are correct and I'm not sure what I am doing wrong. I am doing everything as explained to me in class. I'm so confused...
    Last edited: Nov 19, 2008
  2. jcsd
  3. Nov 18, 2008 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Have you been taught about conservation of energy, and the potential energy of a spring?

    Also, is there supposed to be a question in part A? I only see a question in B.
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