From 5b9fad7827dd8a1bd2ff32256229c2267b930677 Mon Sep 17 00:00:00 2001 From: eggy Date: Thu, 21 Jan 2021 09:25:07 -0500 Subject: [PATCH] phys: add electric field --- docs/sph3u7.md | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/docs/sph3u7.md b/docs/sph3u7.md index 805bd51..99259d8 100644 --- a/docs/sph3u7.md +++ b/docs/sph3u7.md @@ -876,6 +876,13 @@ $$F_E \propto q_1q_2 \propto \frac{1}{r^2}$$ The equation that describes the force between charges is as follows, where $k$ is a constant with the value $8.99×10^9\text{ m}^{-2}\text{C}^{-2}$: $$F_E = \frac{kq_1q_2}{r^2}$$ +### Actual electric fields + +Similar to a gravitational field, the force an object experiences is dependent on both charges but the **field** around an object is only reliant on one. The **field strength** $ε$ is the force per unit of charge and is equal to: +$$\vec{ε}=\frac{F_e}{q}$$ + +The direction of the field depends on its charge — by convention, all test charges are assumed to be **positive**, so vector arrows will point **away** from a positive source and **toward** a negative source. + ## 6.1 - Circular motion Circular motion is any motion along a circular path. The instantaneous velocity of an object in circular motion at any point is always tangent to its point on the circle, so the difference between any two velocities ($\Delta \vec{v}$) is radial (lies along the radius).