As we know that Newton's law considers vacuum as empty, force between objects passing through action at a distance. But in Electromagnetism, vacuum is not considered as empty but considered as continuum, force between objects passing through vacuum. It means that Newton's law may not work if vacuum must be considered. We know that on the electromagnetic wave propagation path, the direction of electric field at a point changes periodically. If there is a charged object at the point also changes its charge property periodically with the same frequency, then the electric field force direction on the object will not change. Therefore, the object will do directional movement. Based on this, it is possible to design a spacecraft does not follow Newton's law. And the calculation suggests that the thrust can be much higher than radiation pressure. With the Electromagnetic Momentum Conservation Equation, this paper proved that in a limited space, Newton's second law may not work although it still work in the whole universe. Also with the Electromagnetic Momentum Conservation Equation, this paper explained why in quantum mechanics at the particle level, particles usually do not follow Newton's second law.