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Formula involving the change in a kinetic energy

  1. Apr 16, 2009 #1
    I'm looking for a formula involving the change in a kinetic energy, I have a 120 N force applied at an angle of 30 degrees above the horizontal to a 4kg box. The box moves a horizontal distance of 8 meters. The change in the kinetic energy of the box is:

    Just looking for a formula to figure this one out
  2. jcsd
  3. Apr 16, 2009 #2


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    The work done by the force on the box=Change in kinetic energy of the box.
  4. Apr 18, 2009 #3
    Hi,...What equations do you have for work? Calculate the vector components of the 120N force. This will simplify the problem for you.

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  5. Apr 18, 2009 #4


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    If you assume the initial velocity is 0, you know that the final energy of the box is E = K + V, K being the kinetic energy and V being the potential. If gravity is involved, your potential V is mgh. If not, it's 0. You also know that your total energy, or the work done to the box, is equal to [tex]F \cdot d\overrightarrow x [/tex]. Break down the force into its components to determine the work done.
    Last edited: Apr 18, 2009
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