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Homework Help: Work done by gravity

  1. Oct 19, 2005 #1
    I'm sick of this stuff

    A 2.52kg block is pushed 1.54m up a vertical wall with constant speed by a constant force of magnitude of F applied at 63.6 degrees with the horizontal. The coefficient of friction is .574. Find the magnitude of the work done by the force of gravity.

    This is what I did:

    Apparently it's wrong and I don't understand why. I drew the diagram and the force of gravity is going down.

    I already found F=38.648N and the work done by F, 53.265J for a previous problem but I don't think those results will help.
  2. jcsd
  3. Oct 19, 2005 #2
    Please tell me what mgh is equal to, and you will have solved your problem. (I dont mean the number, I mean look it up in your book and see what its called). :-)
  4. Oct 20, 2005 #3


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    Homework Helper

    the work, W, done by a force, F, acting on a body while it is displaced through a distance d (a long a straight line), is given by
    W = Fd cos(theta)
    where theta is the angle between the the force and the displacement. The direction of the force and the displacement does not come into consideration in this calculation of the work.
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