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Joules required to accelerate 1kg of mass

  1. Dec 11, 2008 #1
    1. The problem statement, all variables and given/known data
    how many joules of energy are required to accelerate 1 kg of mass from rest to a velocity of 0.866c?

    I tried the relativistic kinetic energy equation, but I feel like it's totally incorrect.


    2. Relevant equations
    KE = [(m0c^2) / √(1-v^2/c^2)] - m0c^2
    E = KE + m0c^2



    3. The attempt at a solution
    KE = [(1 kg*m^2/s^2) / √(1 - (0.866c)^2)] - (1 kg*m^2/s^2)
    KE = [(1 kg*m^2/s^2) / √(1 -0.75 m^2/s^2) - (1 kg*m^2/s^2)
    KE = [(1 kg*m^2/s^2) / (0.5 m/s)] - (1 kg*m^2/s^2)
    KE = 2 kg*m/s - 1 kg*m^2/s^2
    KE = 1 J
     
  2. jcsd
  3. Dec 11, 2008 #2

    tiny-tim

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    Hi ally1h! :smile:
    one joule! :rofl: :rofl:

    Hint: what happened to your c2? :wink:
     
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