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Homework Help: A solid ball - kinetic energy and angular speed

  1. Feb 24, 2004 #1
    A solid ball of mass 1.30 kg and diameter 19.0 cm is rotating about its diameter at 65.0 rev/min.

    What is its kinetic energy?????

    Also, if an additional 2.60 J of energy are supplied to the rotational energy,

    what is the new angular speed of the ball?????
  2. jcsd
  3. Feb 24, 2004 #2


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    Rotational kintic energy is given by

    [tex] {KE = \frac 1 2 I \omega^2 [/tex]

    Where I is the moment of initera and [tex]\omega[/tex]= angular velocity.
  4. Feb 24, 2004 #3
    Thanks alot

    That doesn't help any
  5. Feb 24, 2004 #4
    Were you given that, for a solid sphere, I=2MR2/5 ?

    How many radians are there in a revolution?
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