A point charge +q of mass m, (m,+q) is placed at point P along the x-axis where V_r(infinity) is known. The charge (m, +q) is observed to have a velocidy in the +x direction of the magnitude v_x. At a later time (m, +q) is observed to be at a second point -|y| units along the y-axis where the potential is given by 3V_r(infinity). Find the expression for the new velocity at the second point.