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Homework Help: Angular Speed question

  1. May 5, 2012 #1
    1. The problem statement, all variables and given/known data

    . The angular speed of an automobile engine is increased at a constant rate from 140 rad/s to
    200 rad/s in 20 s. The number of radians through which the engine turns during this 20-s
    interval is

    2. Relevant equations

    3. The attempt at a solution
    I didnt know where to begin with this question, or know of an equation to start with. so a general hint in the right direction would be very appreciated.
  2. jcsd
  3. May 5, 2012 #2
    What's the average speed over the 20 seconds?
  4. May 5, 2012 #3
    3 rads/s^2
    Last edited: May 5, 2012
  5. May 5, 2012 #4
    That's not the average angular speed. That's the average angular acceleration. What's the average angular speed?
  6. May 5, 2012 #5
    soo, 170 rads/s then?
  7. May 6, 2012 #6
    Sooo, if the average rotational speed is 170 rad/s, and the engine runs for 20 s, how many radians does it rotate through?
  8. May 6, 2012 #7
    oh ok ,so it would just be 3400 then. Thanks for your help!
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