In triangle ABC, the electric force at point A due to a continuous charge distribution along side BC is directed along the bisector of angle BAC. The forces from the left and right halves of BC have equal magnitudes but opposite directions, leading to cancellation of their components perpendicular to the bisector. This results in the net electric force aligning with the angle bisector. The discussion emphasizes understanding the symmetry of the charge distribution and the resultant forces at point A. The conclusion is that the electric force direction at point A is determined by the geometric properties of triangle ABC.
