CoulombsLaw 2005-05-12 11:21:16 2005-05-13 12:47:32 Definition \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb} Coulomb's law describes the electrostatic force between electric charges. Coulomb was the first scientist to measure the force using a torsion balance and he discovered that the attraction or repulsion force increases or decreases inversely as the square of the distance between the charges. As an equation Coulomb's law is given as \begin{center} $F = k \frac{q_1 q_2}{r^2}$ \end{center} This equation only gives the magnitude of the force, but we must also take into account the direction of the force. Similar to gravity, the force between the charges acts along a line between them. Coulomb's law in vector form is \begin{center} $ \vec{F} = k \frac{q_1 q_2}{r_{12}^3} \hat{r_{12}} $ \end{center} Some explanation is needed for the variables. $r_{12}$ is the distance between the two charges. More to come on how Coulomb used a torsion balance to come up with this relationship...