## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)

We can write an expression for the particle's initial kinetic energy when the particle's speed is $v$. $KE_0 = \frac{1}{2}mv^2$ We can find the particle's kinetic energy when the speed is $3v$. $KE = \frac{1}{2}m(3v)^2$ $KE = 9\times ~\frac{1}{2}mv^2$ $KE = 9\times ~KE_0$ The particle's kinetic energy increases by a factor of 9.