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Can kinetic energy be added linearly?

  1. Feb 10, 2013 #1
    According to special relativity, velocity cannot be added to another velocity linearly. But I was thinking, what about kinetic energy? K.E. = mv2/2. As velocity increases, the object's mass also increases. The way I see it, the increase in mass "compensates" for the less-than-expected increase in velocity (as predicted by classical mechanics). So am I right in saying, kinetic energy can be added linearly?

    Does what I said above agree with relativistic K.E. equation: K.E. = ([itex]\gamma[/itex]-1)mc2 ?
  2. jcsd
  3. Feb 10, 2013 #2


    Staff: Mentor

    Have you actually checked the math?

    This is the correct equation; so have you checked to see what happens when you transform between frames?
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