Kinetic Energy as a Function of Position

The velocity of a particle of mass m moving along the x-axis is described by the function $v = \alpha x^2$, where x is the position and $\alpha$ is a constant. Given that $m = 2\ \mathrm{kg}$ and $\alpha = 3\ \mathrm{m}^{-1}\mathrm{s}^{-1}$, determine the position x at which the particle’s kinetic energy is 8 J.