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Homework Help: Kinetic Energy

  1. Feb 11, 2007 #1
    Hi, I know the kinetic energy equation is

    Kinetic Energy(J) = 0.5 x Mass (Kg) x velocity² (m/s)

    So how do I rearrange it. Ive been having problems with it

    I have a question here

    What is the weight of an object travelling at 2m/s with 2J of kinetic energy?

    the answer is 10N, but how?

  2. jcsd
  3. Feb 11, 2007 #2


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    Homework Helper

    If you know the velocity and the kinetic energy of the object, what can you calculate from the definition of kinetic energy? You wrote it down already.
  4. Feb 11, 2007 #3
    write it like this
    then you need to get weight from mass.
  5. Feb 11, 2007 #4
    1N so weight is

    1 x 10 = 10N/Kg?
  6. Feb 11, 2007 #5


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    Homework Helper

    If you round up g to equal 10, then you have W = mg = 1 [kg] * 10 [m/s^2] = 10 [kg m /s^2] = 10 [N] ! Watch out for units!
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