Posted by **Katie** on Friday, January 18, 2013 at 10:51am.

The kinetic energy of a proton is half its internal energy. What is the proton's speed?

Kinetic energy is (Yu - 1) (mp) (c)^2

= 1/2 (mp) (c)^2

Yu = 1.5

Yu = 1/(square root) 1 - (u/c)^2

1/(square root) 1 - (u/c)^2 = 1.5

u= 0.745c

How do I solve for u? I'm extremely confused on how to do this. I know you square 1/(square root) 1 - (u/c)^2 to both sides esp. 1.5 to get rid of the square root. But up to there I'm confused to how to solve for u