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Homework Help: Can you help me explain how to find angular velocity?

  1. Feb 27, 2013 #1
    A machinist turns the power on to a grinding wheel, at rest, at time t = 0 s. The wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 69 rad/s. The wheel is run at that angular velocity for 33 s and then power is shut off. The wheel decelerates uniformly at 2.9 rad/s2 until the wheel stops. In this situation, the average angular velocity in the time interval from t = 0 s to t = 25 s is closest to:

    I know that 1st there is constant acceleration, then constance velocity, and then constant deacceleration.

    im really confused, the answer is 55 rad/s, but i dont know how to get the answer
  2. jcsd
  3. Feb 27, 2013 #2


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    2017 Award

    Staff: Mentor

    Did you draw a sketch of the angular velocity as function of t?
    If you have such a sketch, how can you get the average value between two points?
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