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Homework Help: Work done by force moving a particle

  1. Mar 3, 2007 #1
    1. The problem statement, all variables and given/known data

    What work is done by a force (in newtons) F = 3.1xi + 3.1j, with x in meters, that moves a particle from a position r1 = 2.1i + 2.5j to r2 = - -4.9i -3.9j?

    2. Relevant equations

    Work=integral(Fdx)

    3. The attempt at a solution

    W1=integral of Fxdx = integral (3.1x)dx
    = 1.55x^2 evaluated at x2=-4.9 and x1=2.1.
    = [(1.55(-4.9)^2)-(1.55(2.1)^2)]
    = 30.38 J
    W2=integral of Fydy = integral (3.1)dy
    = 3.1[(-3.9)-(2.5)]
    = -19.84 J
    Wnet = W1+W2
    Wnet = 30.38-19.84
    Wnet = 11 J

    But my answer, 11 J, is incorrect...
     
  2. jcsd
  3. Mar 4, 2007 #2

    arildno

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    Science Advisor
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    Gold Member
    Dearly Missed

    This is totally incorrect, on several levels.

    To give you a hint of how to solve this properly, answer the following question:
    Is F a conservative force?
     
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