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Homework Help: Static Friction Coefficient

  1. Mar 1, 2009 #1
    1. The problem statement, all variables and given/known data
    What is the minimum coefficient of static friction necessary to allow a penny to rotate without sliding off a 33.5rpm record (diameter of these old-fashioned records is 0.3), when the penny is placed at the edge of the record. Ignore the size of the penny.

    3. The attempt at a solution
    I know the equation to determine the static friction coefficient. However, I am clueless as to how to proceed from here.
  2. jcsd
  3. Mar 1, 2009 #2


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    Homework Helper

    Which force slides off the penny from the record? What is its magnitude?
    What is the direction and magnitude of the frictional force?
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