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I'm lost. Help?

  1. Feb 15, 2009 #1
    1. The problem statement, all variables and given/known data
    A carton is given an initial speed of 3.0 m/s up a 22.0 degree plane. a.) How far up the plane will it go? b.) How much time elapses before it returns to its starting point? Ignore friction.

    2. Relevant equations

    3. The attempt at a solution
    I have no clue. If someone could point me in the right direction and try to explain what's going on I would very much appreciate it.
  2. jcsd
  3. Feb 15, 2009 #2
    I've been trying to figure it out. I know I'm supposed to break it into 2 equations, but I don't know how to express the 3.0 m/s velocity in the x equation.



    Is that right? If it is I still don't know where to go from here
  4. Feb 15, 2009 #3


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    Gold Member

    Use the equation vf^2 = vi^2 + 2(a_x)(s).
  5. Feb 15, 2009 #4
    But I don't know the time, nor the acceleration.
  6. Feb 15, 2009 #5


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    Gold Member

    You have both the initial and final velocities so all you need right now is the acceleration in the x direction, which you can find by using mg = Fncos(theta) and a_x = gsin(theta).
  7. Feb 15, 2009 #6
    Oh, ok. Now I get it. You put an (s) in the equation which threw me off. I found the distance and the time it took to reach the max point, but how do I get the total time? Should I just double the time it took to get to the highest point?
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