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Simple harmonic motion question

  1. May 17, 2009 #1
    1. The problem statement, all variables and given/known data
    A mass of 10g is suspended from a spring of unstreched length 80cm. The extension produced is 1cm. The mass is pulled down a further 0.5cm and then released. Find:
    a) the period of motion
    b)the maximum speed of the mass
    c) the max Ke of the mass
    d)the tension in the spring when the mass is o.1cm below the equilibrium position
    e) the max potential energy stored by the spring
    f) the energy released by the spring when the mass moves from its lowest to the equilibrium position.

    Any help of any sort will be greatly appreciated as i've only started studying this topic and finding it hard to understand. Many Thanks.
  2. jcsd
  3. May 17, 2009 #2


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    Use the information given to find the spring constant (hint: spring force = mg when the mass is at equilibrium, which occurs when the extension is 1cm).
    Then use the sping constant and the amplitude A= 0.5 cm to find all the answers.
  4. May 17, 2009 #3


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    How about you start by calculating the spring constant from the information that was given.

    Hint: what is the force that causes the spring to extend?
  5. May 17, 2009 #4
    thanks for you help.
    So for the spring constant:
    mg=w, 0.01*9.81= 0.0981 which i think is the force extending the spring?
    if the spring constant = f/x is so then k = 9.81?
    if thats the case then to calculate the period could i use T = 2pi ROOT(m/k)?
  6. May 17, 2009 #5


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    Looks good!!
  7. May 17, 2009 #6
    for part b am i correct in using this equation: v=wROOT(A^2-x^2) and if so because max speed is reached at the equilibirum position would i take x as 0?
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