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Homework Help: Rectilinear Motion Problem

  1. Sep 11, 2009 #1
    1. The problem statement, all variables and given/known data
    A block of wood is projected up an inclined plane with initial speed v0. If the inclination of the plane is 300 and the coefficent of sliding friction uk=0.1, find the total time for the block to return to the point of projection.

    2. Relevant equations

    3. The attempt at a solution
    To be honest I'm not sure where to start with this. I'm just asking for a bit of
    guidance on how to start the question.
  2. jcsd
  3. Sep 11, 2009 #2
    Can you set it up if there is no friction involved? Have you made a FBD?
  4. Sep 11, 2009 #3
    I'm not sure about setting it up without involving friction but I have made a FBD diagram.
  5. Sep 12, 2009 #4
    What can you tell about the initial conditions parallel to the incline?
  6. Sep 12, 2009 #5
    Oh I solved the problem (a good nights sleep does wonders apparently), thank you for the help though.
  7. Sep 20, 2009 #6
    Can you tell me how you did it? I am really stuck on this problem
  8. Sep 20, 2009 #7
    The most important thing about the question is setting up the FBD once you get that the rest is simple. You need to analyze the system in two steps, the first one being up hill and the second downhill.

    You should be able to first find the acceleration uphill, which can then be used to determine the time going up the incline , kinematic equations will be helpful in this regard. You can then use the information to find the time going down the incline.
  9. Sep 20, 2009 #8
    Okay, I will give it a shot and if I still have troubles do you mind if I post back on here and you could help me out? Thanks!
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