A small particle has charge $-4\mathrm{.}60$ CC and mass $2\mathrm{.}60104$ kgkg $.$ It moves from point AA$,$ where the electric potential is VAVA $=100$ V $,$ to point B$,$ where the electric potential VB $=870$ V is greater than the potential at point A$.$ The electric force is the only force acting on the particle. The particle has a speed of $5\mathrm{.}30$ m$/$s at point A$.$