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Homework Help: Centripital force question

  1. Jan 5, 2010 #1
    A bicycle wheel has an angular acceleration
    of 1.4 rad/s2.
    If a point on its rim has a tangential accel-
    eration of 49 cm/s2, what is the radius of the
    wheel?
    Answer in units of m.

    I know that there should be some way to relate the angular acceleration and the tangential acceleration but I can't figure it out.

    I tried to relate the angular acceleration to angular speed to then find delta theta so then I could plug into S=Rtheta. The only problem is that I don't have the angular speed. I know that there has to be an easy way to do this problem.


    3. The attempt at a solution
     
  2. jcsd
  3. Jan 5, 2010 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hail BoldKnight399! Welcome to PF! :smile:

    (erm :redface: … tangential is more-or-less the opposite of centripetal :rolleyes:)
    cm/s2 = radian/s2 times cm/radian

    (just like cm/s = radian/s times cm/radian :wink:).

    So what is cm/radian in this case? :smile:
     
  4. Jan 5, 2010 #3
    knew it had to be simple and I was just missing it. Thank you!
     
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