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Homework Help: Kinetic energy, help ?

  1. Feb 29, 2012 #1
    kinetic energy, help!!?

    A 3kg object has a velocity < 6i -1j > m/s. What is its kinetic energy at this moment? According to the book I'm using the ans is 60J but I get 55.5 J.......What em I doing wrong???
  2. jcsd
  3. Feb 29, 2012 #2
    Re: kinetic energy, help!!?

    They probably just rounded their answer. If you use sig figs, there's only one sig fig in < 6i -1j >, so they rounded 55.5 to 60 to conserve sig figs.
  4. Feb 29, 2012 #3
    Re: kinetic energy, help!!?

    i'm getting the same answer as you
  5. Feb 29, 2012 #4
    Re: kinetic energy, help!!?

    Hey thanks guys, I was really going nuts here trying to figure it out, it only made sense that the answer was rounded.
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