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Homework Help: Work pushing a mass up a plank

  1. Aug 24, 2008 #1
    1. The problem statement, all variables and given/known data
    force F is required to push a crate of mass m up a plank of length L into a truck whose platform is a vertical distance h above the road.

    a)How much work is done pusing the crate up the plank m=100kg, L=5m, F=490N h=1.2m
    b)what is the increase in PE of the crate once the crate is on the platform


    2. Relevant equations
    W=Fxd
    PE=mgh



    3. The attempt at a solution

    ok so my working is

    W=Fxd
    W=490Nx5m
    W=2450N

    and

    PE=mgh
    PE=(100kg)(9.8ms-1)(1.2m)
    PE=1176 N

    Hmmmmmmm...........i think they are right
     
  2. jcsd
  3. Aug 24, 2008 #2

    Defennder

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    Homework Helper

    Yeah it looks ok, provided no friction is involved and F is directed along the length of L.
     
  4. Aug 24, 2008 #3
    Excellent i finally got one right by myself!!!
     
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