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Homework Help: KE of ball rolling in a plane

  1. Sep 25, 2011 #1
    1. The problem statement, all variables and given/known data

    Uniform ball or mass m and radius r rolls on a horizontal plane without sipping, at the same time moving along a circular path of radius R. Speed of the center of mass is constant and equals v. Find it's kinetic energy.

    2. Relevant equations

    I=2/5 m r^2

    3. The attempt at a solution

    KE of ball's translation T1=(m v^2)/2

    KE of ball's rotation T2=(I w^2)/2 ( w - angular velocity, from w r = v => w= v/r)

    My problem is with the ball moving along a circle of radius R. Where does it come into play?
    Do i have to add the KE of ball rotation around the center of the circle?

    Any help will be appreciated.
  2. jcsd
  3. Sep 25, 2011 #2

    Doc Al

    User Avatar

    Staff: Mentor

    The ball is also rotating about a vertical axis as it moves in the circle.
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