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Finding Change in Kinetic Energy

  1. Dec 4, 2011 #1
    1. The problem statement, all variables and given/known data
    A mass of 8.50 kg is travelling 7.50 m/s
    [up]. It is acted on by a force of 340 N [up]
    over a displacement of 15.0 m [up].

    What is the change in kinetic energy


    2. Relevant equations
    Ek = 1/2mvsquared. F = mv. w = fd


    3. The attempt at a solution

    I tried doing the equation Ek = 1/2mvsquared, and was off by 3000 or so.
     
  2. jcsd
  3. Dec 4, 2011 #2

    cepheid

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    Staff Emeritus
    Science Advisor
    Gold Member

    That's because you probably used the INITIAL speed. The speed will change, because there is a force acting on the object.

    1. Figure out the work done on the object (don't forget to consider all forces acting on it).

    2. Use the work-energy theorem to figure out the object's change in kinetic energy given the work done in part 1.
     
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