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Homework Help: Friction and a tablecloth.

  1. Jul 12, 2009 #1
    1. The problem statement, all variables and given/known data
    If you have courage and a tight grip, you can yank a tablecloth from under the dishes on a table. What is the longest time in which the cloth can be pulled out so that a glass 6 in from the edge comes to rest before falling off the table? Assume that the coefficient of friction of the glass sliding on the tablecloth or sliding on the table top is 0.5.

    2. Relevant equations
    [tex]F_f=\mu mg[/tex]

    3. The attempt at a solution
    Okay, so the force due to friction is [tex]F_f=\mu mg[/tex]. The force will be applied for some maximum time: [tex]F_ft_{max}=\mu mgt_{max}[/tex]. I'm not sure how to continue.

    Thanks for your help.
  2. jcsd
  3. Jul 12, 2009 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Hint: What's the acceleration of the glass?
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