Helping a confused particle!

Electricity and Magnetism Level 3

A positively charged particle was sitting idle at the origin of a Cartesian coordinate system. The particle is then subjected to an electric field $\textbf{E}=E_{0}\cos\big(\frac{\pi}{2}+\omega t\big)\hat{\imath}$ at time $t\geq0,$ where $E_{0}$ is a positive constant scalar and $\omega$ is the angular frequency of oscillation of electric field in $\text{rad}/\sec.$

What will the particle do after $t=0?$