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Homework Help: Linear acceleration and a grinding wheel

  1. Dec 2, 2007 #1
    1. The problem statement, all variables and given/known data
    A grinding wheel 0.35 m in diameter rotates at 2500rmp. What is the linear acceleration of a point on the edge of the grinding wheel?
    For the linear acceleration, should it be atotal=atan+aR? Should we find both tangential acceleration and centripetal acceleration? But on the answer key, it's only centripetal acceleration. i dont' know why? But also I can not find tangential acceleration since I dont know the time. Hope you can help. thanks.
     
  2. jcsd
  3. Dec 3, 2007 #2
    Should we find both tangential and centripetal acceleration?
     
  4. Dec 3, 2007 #3

    PhanthomJay

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    The wheel is rotating at constant angular velocity and constant tangential speed; ; therfore, it has no tangential acceleration, just radial (or centripetal) acceleration.
     
  5. Dec 3, 2007 #4
    How do you know it's constant angular velocity? Because it didn't say anything about acceleration of angular velocity?
     
  6. Dec 4, 2007 #5

    PhanthomJay

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    It said it it is moving at 2500rpm. That is a constant angular velocity. If it was accelerating, it would have stated such, or at least made a veiled reference to it and given other data. It is like saying that a train is moving at 90mph......there is no reason to believe that the train is accelerating if it is not stated, that is, the 90 mph is assumed a constant speed.
     
  7. Dec 5, 2007 #6
    Ok. I got it. Thank you.
     
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