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Homework Help: Oscillation Problem

  1. Feb 13, 2010 #1
    1. The problem statement, all variables and given/known data
    A block attached to a spring is displaced from equilibrium to the position x = +4.9 m and released. The period is 0.5 s . At what positions and times during the first complete cycle do the following condition occur:

    | v | = 0.5 v_{max}, Where v_{max} is the maximum speed?

    2. Relevant equations
    none i suppose.

    3. The attempt at a solution
    I believe the s(t)= 4.9 sin (4pi(t)+0.5pi)
    v(t) = 19.6pi cos (4pi(t)+0.5pi)

    there for 0.5 max velocity is = 9.8pi ---> (19.6pi/2)

    so for velocity without breaking the phase constant:

    4pi (t) + 0.5pi = pi/3 5pi/3

    i dont think i am right, can any one clear it up?
  2. jcsd
  3. Feb 13, 2010 #2


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    Science Advisor
    Homework Helper

    Hi phat2107! :wink:

    Yes, that looks ok … |v| is half vmax when |cos| = 1/2 …

    so that's when t and s = … ? :smile:
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