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Homework Help: What is the average angular velocity?

  1. May 2, 2008 #1
    The angle through which a rotating wheel has turned in time t is given by \
    theta = a t - b t^2+ c t^4, where theta is in radians and t in seconds.

    What is the average angular velocity between t = 2.0 s and t =3.3 s?
    If a = 9.0 rad/s, b = 16.0 rad/s^2, c = 1.6 rad/s^4

    2. Relevant equations
    d(theta)/dt = omega

    omega average = change in theta / change in time

    3. The attempt at a solution

    omega =a-2bt+4ct^3

    i got omega = 63.1 rad/s (omega =a-2bt+4ct^3 )

    and 2nd time i got 19.0826 (change in theta / change in time)

    both is wrong when i put on the webs

    can anyone help me please
  2. jcsd
  3. May 3, 2008 #2
    Since it's asking for an average, you should use the second equation you listed. I don't know how you got the answer you posted, but using the values you are given for t, find your initial and final thetas. Change in theta is final minus initial.

    Write it all out...perhaps you put it into your calculator incorrectly?
  4. May 3, 2008 #3
    change in theta / change in time

    yep this work answer is 50

    45-(-20) = 65/1.3 = 50

    i put in 45-20 on my calc that why is wrong thank for help
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