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Rotational Velocity and Acceleration

  1. Apr 8, 2012 #1
    1. Electric toothbrushes can be effective in removing dental plaque. One model consists of a head 1.1 cm in diameter that rotates back and forth through a 70.0 angle 7600 times per minute. The rim of the head contains a thin row of bristles. (See the figure )Assuming that the toothbrush has constant angular acceleration in each of the directions it turns, find the angular acceleration (in rad/sec2 ) of the rotating head and the tangential acceleration (in m/s2 ) of the bristles.


    What is the rotational acceleration in rad/sec2

    What is tangental accelration in m/s2
     
    Last edited: Apr 8, 2012
  2. jcsd
  3. Apr 8, 2012 #2

    gneill

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    Staff: Mentor

    Seriously? A toothbrush 1.1 inches in diameter? :surprised Is it for horses?
     
  4. Apr 8, 2012 #3
    Oops. that should say 1.1 cm
     
  5. Apr 8, 2012 #4

    gneill

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    Staff: Mentor

    Phew! You had me worried for a moment there :smile:

    So assuming that the brush goes from zero to angle seventy degrees in a half period, what is the required angular acceleration?
     
  6. Apr 8, 2012 #5
    realllly unsure bud
     
  7. Apr 8, 2012 #6

    gneill

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    Staff: Mentor

    Well, if it goes back and forth 7600 times every minute, what's the period for one cycle?
     
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