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Homework Help: Quick Question

  1. Nov 10, 2007 #1
    1. The problem statement, all variables and given/known data

    I did the first 3 parts of the question, but I can't seem to get the right answer on the last one.

    (a) How much work is done by the horizontal force Fp on the 20 kg block when the force pushes the block 3.6 m up the 30° frictionless incline?
    467.7 J
    (b) How much work is done by the gravitational force on the block during this displacement?
    -352.8 J
    (c) How much work is done by the normal force?
    0 J
    (d) What is the speed of the block (assume that it is zero initially) after this displacement?

    2. Relevant equations

    3. The attempt at a solution

    I know that W = .5m(v^2) in this case, and since on D, (thats the one I have a question on), I'm trying to find Velocity, I can use this formula. I tried

    467.7 = .5m(v^2)

    and got v=6.83 but thats wrong.

    Thank you so much for your help!!

  2. jcsd
  3. Nov 10, 2007 #2
    What's the TOTAL work done on the object?
  4. Nov 10, 2007 #3
    Hey, I didn't think to do that, THANK YOU I got it right!!!! =) =)
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