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Calculating Rotational Acceleration of a Wheel

  1. Dec 1, 2009 #1
    1. The problem statement, all variables and given/known data
    A rotating wheel requires 3.05 s to rotate through 37.0 revolutions. Its angular speed at the end of the 3.05 s interval is 97.1 rad/s. What is the constant angular acceleration of the wheel?


    2. Relevant equations
    Well from basic calculus I know that acceleration is equal to (dV/dT) or the derivative of velocity over derivative of time.

    That is the only pertinent equation I can think of for this problem.


    3. The attempt at a solution

    I used the velocity, 97.1 rad/s, and divided it by the time, 3.05s.

    (97.1/3.05)= 31.84 rad/s^2

    According to the online homework this is incorrect. I cannot think of any other way to calculate it since the radius is not given.


    1. The problem statement, all variables and given/known data

    A racing car travels on a circular track of radius 230 m. Suppose the car moves with a constant linear speed of 53.0 m/s.

    (b) Find the magnitude and direction of its acceleration.

    Part (a) had me calculate the velocity which came out to 0.23 rad/s. The velocity is correct.


    2. Relevant equations
    a= linear acceleration
    A=rotational acceleration
    R=radius

    A=a/R

    circumference = 2piR

    3. The attempt at a solution

    I figured since it says a constant linear acceleration then the angular acceleration=0 because A=(0)/(230) = 0. This answer is incorrect according to the online homework. I'm not sure what else to do.
     
    Last edited: Dec 1, 2009
  2. jcsd
  3. Dec 1, 2009 #2

    Kurdt

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