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Homework Help: Work done on the object problem

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

    A single force acts on a 5.0 kg particle-like object in such a way that the position of the object as a function of time is given by x = 3.0t - 4.0t^2 + 1.0t^3, with x in meters and t in seconds. Find the work done on the object by the force from t = 0 to t = 2.0 s.

    2. Relevant equations

    x=3.0t-4.0t^2+1t^3
    W=Fd
    W=integral(Fdx)

    3. The attempt at a solution

    So when t=0, x=0.
    When t=2, x=-2
    displacement= -2-0 = -2m

    W=Fd
    F=ma=(5)(9.8)=49

    W=(49 N)(-2 m)
    W= -98 J
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Mar 3, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    No. What makes you think that the acceleration equals 9.8? Is the acceleration even constant?

    Hint: Consider the change in KE of the object.
     
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