From f95a7fc6f84185a5abe1ef94df03fd5d41516beb Mon Sep 17 00:00:00 2001 From: eggy Date: Mon, 16 Jan 2023 21:24:04 -0500 Subject: [PATCH] ece106: add dipoles --- docs/1b/ece106.md | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/docs/1b/ece106.md b/docs/1b/ece106.md index a9d124f..53f4469 100644 --- a/docs/1b/ece106.md +++ b/docs/1b/ece106.md @@ -136,6 +136,8 @@ The formula for the **moment of inertia** of an object is as follows, where $r_\ $$dI=(r_\perp)^2dm$$ +If the axis of rotation is perpendicular to the plane of the object, $r_\perp=r$. If the axis is parallel, $r_\perp$ is the shortest distance to the axis. Setting an axis along the axis of rotation is easier. + !!! example In a uniformly distributed disk rotating about the origin like a CD with mass $M$ and radius $R$: @@ -167,3 +169,11 @@ Please see [SL Physics 1#Charge](/sph3u7/#charge) for more information. **Coulomb's law** states that for point charges $Q_1, Q_2$ with distance from the first to the second $\vec R_{12}$: $$\vec F_{12}=k\frac{Q_1Q_2}{||R_{12}||^2}\hat{R_{12}}$$ + +### Dipoles + +An **electric dipole** is composed of two equal but opposite charges $Q$ separated by a distance $d$. The dipole moment is the product of the two, $Qd$. + +The charge experienced by a positive test charge along the dipole line can be reduced to: +$$\vec F_q=\hat x\frac{2kQdq}{||\vec x||^3}$$ +