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Homework Help: Physics help KE, W, PE

  1. Feb 27, 2007 #1
    https://mywebspace.wisc.edu/dxiong4/physics%201.bmp?uniq=-w1zg99 [Broken]

    for part b i am to find work of gravity, and to do so what i did was

    mass*gravity*cos 22*distance(12) to get 436.14, but it seems that it is wrong

    i've tried mass*gravity*distance (12)=470.4 and still is not the correct answer, can someone plz explain to me what i am doing wrong? thx
     
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Feb 28, 2007 #2

    cristo

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    Check the red part; you want the component of the weight acting parallel to the slope.
     
    Last edited by a moderator: May 2, 2017
  4. Feb 28, 2007 #3

    HallsofIvy

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    Conversely, you want the upward component of displacement-
    [itex]sin(\theta)[/itex], not [itex]cos(\theta)[/itex]. It's the same as cristo's point.
     
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