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A mass of 1x10^-16 kg is traveling, what is its kinetic energy ?

  1. Mar 12, 2010 #1
    1. The problem statement, all variables and given/known data
    A mass of 1x10^-16 kg is traveling at 0.5 c to the nearest hundredth joule what is its kinetic energy?


    2. Relevant equations

    Et=KE + mc^2=Jmc^2
    KE=mc^2(J-1)
    KE=mc^2(1/sqrt(1-v^2/c^2)-1)=

    3. The attempt at a solution
    This is where i am stuck putting the whole thing in the calculator i guess...
    (1X10^-16)(.5)^2(1x10^-16)(3x10^8)^2(1/sqrt(1-0.5^2)^2-1)
    answer is 1.39, i keep getting something else?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Mar 12, 2010 #2

    sylas

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    Science Advisor

    So far so good.

    This doesn't look much like the formula you just gave. The formula you had was mc^2(1/sqrt(1-v^2/c^2)-1)
     
  4. Mar 12, 2010 #3
    How should i set the equation up ?
     
  5. Mar 12, 2010 #4

    sylas

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    Science Advisor

    Just use the formula you gave, with the values for all the variables. I don't know what happened for the numbers... but for example, the mass is 10-16. Mass appears just one in your formula, but twice in the list of numbers you gave for the calculator.

    [highlight](1X10^-16)[/highlight](.5)^2[highlight](1x10^-16)[/highlight](3x10^8)^2(1/sqrt(1-0.5^2)^2-1)​
     
  6. Mar 12, 2010 #5
    Can you show what to input into the calculator to get 1.39J, because that's actually where i am stuck. Thanks
     
  7. Mar 13, 2010 #6

    Redbelly98

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    Homework Helper

    No, that is not how it works at this forum.
    I've used color to match up the numbers in your calculation with the terms in the equation you are using. Notice that the numbers in blue don't correspond to any of the terms from the equation, and so do not even belong in the calculation.
     
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