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Homework Help: Increase in speed, increase in energy

  1. Oct 2, 2009 #1
    1. The problem statement, all variables and given/known data
    an 5kg object speed up from 5m/s(point A) to 10m/s(point B)

    at point A, the energy is 0.5mv2 = 0.5(5)(5)2 = 62.5J
    at point B, the energy is 0.5mv2 = 0.5(5)(10)2 = 250J

    I don't not sure why the energy in the object is increased when it speeds up from point A to point B. suppose the energy in the object should be taken up to increase it's speed isn't?

    or my concept is wrong?
  2. jcsd
  3. Oct 2, 2009 #2


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    Homework Helper

    You have calculated the kinetic energy, the energy due to speed. The greater the speed, the greater the kinetic energy.

    In a real situation some other type of energy would have to decrease to free up the energy needed to increase the speed.
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