Hello there! In my last Electromagnetism lecture, the teacher explained that Newton's 3rd law doesn't work when we "sit" on a charged particle and move at the same velocity while another particle is moving at another v velocitiy perpendicular to ours. How ist it that Newton doesn't work? And how do you explain that if we move along both particles (paralell velocity) the magnetic force is not seen. I suspect that Einsten has something to do with this. Although I haven't taken a special relativity course yet, I read that Einstein came up with his ideas due to these problems in electrodynamics. I'd be very grateful if you could help me understand this.