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Homework Help: How to find the minium coefficient of static friction?

  1. Mar 29, 2010 #1
    1. The problem statement, all variables and given/known data

    For a system (with frictionless pulley) Mewsubk = .25 and the system is initially at rest. The mass of block 1 is 16 kg and the mass of block 2 is 12 kg. Determine the minimum coefficient of static friction needed to prevent any movement.

    2. Relevant equations


    3. The attempt at a solution
    I have no idea how to figure it out.
    I figured out the acceleration to be 2.8m/s^2 because:
    a= 12kg*9.8m/s^2 - .25*16kg*9.8m/s^2/(16kg+12kg)
    I figured out the tension in the connecting string to be 84 N because:

    Any help on how to figure out minimum coefficient of static friction?
  2. jcsd
  3. Mar 29, 2010 #2


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    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi ARJewell ! Welcome to PF! :smile:

    (have a mu: µ and try using the X2 tag just above the Reply box :wink:)
    No, if movement is prevented (or even, in a different question, where the block is just moving), a must be zero! :wink:

    Try again. :smile:
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