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Homework Help: Rotational Kinematics of a CD

  1. Apr 4, 2006 #1
    Can anyone help me with these 2 ?

    1.) A cd with a diameter of 12 cm, speeds up from 0 to 4 rev/s in 3s. What is the tangential acceleration of a point on the outer rim of the disk at the moment when angular speed is a.) 2 rev/s b.) 3 rev/s

    2.) A fisherman reels in a fish and turns the spool on the reel at a rate of 3 revolutions per second. If the radius of the reel is 3.7 cm, what is the linear speed of the fishing line as it is reeled in ?
  2. jcsd
  3. Apr 4, 2006 #2


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    Gold Member

    You need to show some work before we can help.
  4. Apr 5, 2006 #3
    remember to get frequency its 1/t, so convert it the rev/s to Hz. I hope i'm correct?
  5. Apr 8, 2006 #4

    I don't know where to start .. can anyone Help ?
  6. Apr 8, 2006 #5


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    Gold Member

    A formula for tangental acceleration is;

    [tex]\alpha = \frac{a_{t}}{r}[/tex]

    where [itex]\alpha[/itex] is angular acceleration and [itex]a_{t}[/itex] is tangental acceleration.

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