Electromagnetism and Waves question.?

A particle having charge q=+2.70 muC and m m = 0.0250 kg is connected to a string that is L = 2.10 m long and is tied to the pivot point P. The particle, string, and pivot point all lie on a horizontal table. The particle is released from rest when the string makes an angle of 60 degrees with a uniform electric field of magnitude E = 310 V/m. Determine the speed of the particle when the string is parallel to the electric field (point a, figure below).