Lorentz Force

A stationary electric charge placed in a magnetic field feels no force at all; only a moving charge feels a magnetic force, quite different in character from the Coulomb force of Unit 1. When both an electric field $\vec E$ and a magnetic field $\vec B$ act on a moving charge $q$ at once, the total force is the Lorentz force:

$\vec F = q\vec E + q(\vec v \times \vec B)$ …