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Homework Help: Confusing System of Masses Question

  1. Mar 30, 2008 #1
    May somebody please help me on this question, I have no idea even where to begin.

    A 0.5kg wooden block is placed on top of a 1.0kg wooden block. The coefficient of static friction between the two blocks is 0.35. The coefficient of kinetic friction between the lower block and the level table is 0.20. What is the maximum horizontal force that can be applied to the lower block without the upper block slipping?
  2. jcsd
  3. Mar 30, 2008 #2


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    Welcome to PF!

    Hi Keeo! Welcome to PF! :smile:

    Hint: which will slip first, the upper block relative to the lower block, or the lower block relative to the table?

    What is the maximum possible friction force between the upper block and the lower block? :smile:
  4. Mar 30, 2008 #3
    Ok, I think I can help get you started on this one. For ease I'm calling the 1kg block m1 and the .5kg block m2. First think I would do is consider the equation fs= us*N where fs is the force of friction, us is the coefficient of friction and N is the normal force on the block. So, for m1 you would do this: .2*(9.8*1kg) which would then give you 1.96 N as your fs1. Hint: This is in the opposite direction of the applied force. See if that can help start you out and then go from there.
  5. Mar 30, 2008 #4
    Thanks for all of your help it has actually lead me to an answer. Also thank you for welcoming me here.:biggrin:
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