- #1
max8404
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Homework Statement
Thanks for everyone that helped me with the physics questions! I had my physics 2 final today and got a 94! There was a question that I could not figure out for a long time. It goes like this.
What would the velocity of the photon be if the Kinetic energy of the photon equals the rest energy of the photon? Express v in terms of c and anything else. Luckily, the question was a multiple choice, and the correct answer (which I guessed) was sqrt(3)/2 x c
I still cannot figure out why this is true.
Homework Equations
K=1/2mv^2 --> I assume this is the right equation to use...
Er=mc^2
The Attempt at a Solution
Equaling the two would give you:
1/2mv^2=mc^2
v^2=2c^2
v=sqrt(2) x c
This is obviously not true since you can't go faster than the speed of light. Can someone explain to me how the answer is sqrt(3)/2 x c and why I am getting this thing wrong? Am I using the right Kinetic Energy equation??
Thanks!