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Homework Help: Air-Track Cart Oscillating on a Spring, solve for time

  1. Dec 4, 2011 #1
    The problem statement, all variables and given/known data
    The position of a an air-track cart that is oscillating on a spring is given by (14.0cm)cos[(12.0s-1)t]. At what value t after t=0 is the cart first located at x=2.0 cm?


    The attempt at a solution

    y = Acos(wt+∅)

    y = 14cos(12t)
    2 = 14cos(12t)
    (1/7) = cos(12t)
    12t = cos^-1(1/7)
    t = cos^/1(1/7) / 12
    t = 6.816 seconds,
    incorrect.

    Does anyone have any advice on how to proceed with this question?
     
  2. jcsd
  3. Dec 4, 2011 #2

    Doc Al

    User Avatar

    Staff: Mentor

    When finding the angle, be sure to express it in radians. cos^-1(1/7) = ??
     
  4. Dec 4, 2011 #3
    Thank you!
     
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