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Homework Help: Work/Energy Conservation Problem w/ Initial Velocity

  1. Jan 15, 2012 #1
    1. The problem statement, all variables and given/known data
    An applied force of 10.0N acts horizontally on a 0.50kg mass on a floor with the coefficient of friction being 0.40. If the object had an initial speed of 2.00 m/s, determine its speed at 15.0m.

    2. Relevant equations
    General Energy Conservation Formula
    Ek(i) + Ep (i) + Einput(i) = Ek(f) + Ep(f) + Eoutput(f)

    3. The attempt at a solution
    1/2 * 0.5 * 2^2 + (10 * 15) = 1/2 * 0.5 * v^2 + ((0.4)(0.5)(9.8) * 15)
    (hope I wrote it down correctly haha)
    v = 22.1 m/s

    Now I know the answer is supposed to be 2.21 m/s, but I have no idea how I ended up with what seems to be a decimal place in the wrong position. What gives?

    Thanks in advance for the help!
  2. jcsd
  3. Jan 15, 2012 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Your work--and your answer--looks fine to me.
  4. Jan 15, 2012 #3
    So I was correct? The solution key must have been wrong then. Thanks a bunch!
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