A particle of charge q and mass m is subjected to an electric field E = E_0(1- a x^2) in the x -direction, where a and E_0 are constants. Initially…

A particle of charge q and mass m is subjected to an electric field $\displaystyle \mathrm{E}=\mathrm{E}_0\left(1-\mathrm{a} x^2\right)$ in the $\displaystyle x$-direction, where a and $\displaystyle \mathrm{E}_0$ are constants. Initially the particle was at rest at $\displaystyle x=0$. Other than the initial position the kinetic energy of the particle becomes zero when the distance of the particle from the origin is :