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Homework Help: Vertical Circular Motion

  1. Nov 29, 2008 #1
    1. The problem statement, all variables and given/known data

    Picture: http://img151.imageshack.us/img151/9393/physicszn8.jpg [Broken]

    A ball on the end of a string is cleverly revolved at a uniform rate in a vertical circle of radius 60.0 cm, as shown in Fig. 5-33. Its speed is 4.00 m/s and its mass is 0.300 kg.

    (a) Calculate the tension in the string when the ball is at the top of its path.


    2. Relevant equations

    EF = ma


    3. The attempt at a solution

    EF = ma
    Ft + Fg = ma
    Ft = mac - Fg

    Ft = ((mv^2)/r)) + mg
    Ft = 8 - 5.88
    Ft = 2.12

    This answer is incorrect.
     
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Nov 29, 2008 #2
    Recalculate mg.

    ;)
     
  4. Nov 29, 2008 #3
    Wow, I made a huge mistake... I had .6m * 9.8m/s^2 for mg.... lol

    New MG

    0.300kg * 9.8m/sec^2 = 2.94.

    8 - 2.94 = 5.06 N.
     
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