Does Newton's Third Law Always Hold?
Alright, let's get into some basic physics! Very basic 😉, which is where it's easiest to get tripped 😁: In the usual classical regime of our daily lives, i.e. speeds much smaller than the speed of light and length scales much larger than the atomic scale, is the following statement true: "Newton's 3rd law holds true in all situations"? As an example, consider two positive charges q1 and q2 moving along the x and y axes respectively. While the electrostatic Coulomb's force between the two charges is "equal and opposite" on each charge - thus respecting Newton's 3rd law - can the same be said about the magnetic force between the two charges? It is possible to deduce the direction of magnetic forces induced by the charges on each other without carrying out exact calculations of the magnetic field. Go ahead and try it! Once you've put your head to it for a while, look up the last four paragraphs of Section 1.5 of Classical Mechanics by John R. ...