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Homework Help: Centripetal accel

  1. Dec 3, 2005 #1
    Here's a picture http://img215.imageshack.us/my.php?image=physics6ry.png

    A .10kg ball is on a string in vertical circular motion with a radius .80 meters and the whole system is above the ground .20 meters At the top the tangential velocity is 6.0m/s.

    I'm wondering if these are correct:
    1)At the lowest point on the circular path the tangential velocity is 2.0 m/s.
    2)The tension at the top of the circular path is ~2.6 N

    I found the velocity by using KE = PE
    I found the tension of the top by: T = Fc + Fw

    The reason I'm wondering this is because I figured out the speed, and tensions on the top and bottom and I came up with a higher tension in the top than in the bottom...
  2. jcsd
  3. Dec 3, 2005 #2
    At the top, the tension and weight are acting in the same direction:
    T + Fg = mv^2 / r
    so then:
    T= mv^2/r - Fg
  4. Dec 3, 2005 #3
    In addition, for part A, the ball has both kinetic energy and gpe at the top, while at the bottom it should only have gpe.
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