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Homework Help: Angular acceleration of wheel

  1. Apr 11, 2010 #1
    1. The problem statement, all variables and given/known data
    A 70cm diameter wheels accelerates uniformly from 160 rpm to 280 rpm in 4.00s.
    a) it's angular acceleration, and
    b) the radial and tangential components of the linear acceleration of a point on the edge of the wheel 2.00s after it has started accelerating

    w2= 280rpm
    w1= 160rpm
    t = 4.0s
    d= .7m

    2. Relevant equations

    a = w2-w1 / t

    3. The attempt at a solution

    I used that equation for part a, with a= 280rpm - 160rpm /4.0s
    and got a= 30 , but I don't feel that is right. Is there a better equation I could have used?
  2. jcsd
  3. Apr 11, 2010 #2
    The formula you used is fine, but more accurately:
    [tex]\alpha = \frac{{\Delta}\omega}{{\Delta}t}[/tex]
    this gives average angular acceleration over the given time interval.

    You need to specify units in your answer (and you'll find you want to convert it to more logical units)
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