ANSWER: As the electromagnetic career is not a vector field, it is an effective tensor occupation OK, that is kind of technical, so let me try to clarify. An electric charge at rest will interact differently with the x- and y-components of an electric field (the Ex will cause an acceleration in the x-direction, Ey in the y-direction). The full field may be roughly thought of as having six components and an electric charge will respond differently to all six. And, they are all mixed up depending on your motion. If you have a pure electric field but observe it...
