# Chapter 8: Angular Motion and Statics

Difficulty Level:

**At Grade**Created by: CK-12

**Credit**: Charles Hutchins

**Source**: http://www.flickr.com/photos/celesteh/3266906452/

**License**: CC BY-NC 3.0

We have looked at circular motion using the same measures as linear motion. To look at rotation in more detail, though, we need to work in rotational units - measuring the angle rotated through, the angular sped, and angular acceleration.

## Chapter Outline

- 8.1. Angular Momentum
- 8.2. Torque
- 8.3. Two Conditions of Equilibrium
- 8.4. Applications of Equilibrium Conditions

### Chapter Summary

- Angular momentum is defined as the product of rotational inertia and angular velocity.
- Torque is defined as \begin{align*}\tau=rF \sin \theta\end{align*}, where the angle \begin{align*}\theta\end{align*} is the angle between the lever arm \begin{align*}r\end{align*} and force \begin{align*}F\end{align*}. The symbol for torque is the Greek letter tau \begin{align*}(\tau)\end{align*}
- By definition a counterclockwise torque is positive and a clockwise torque is negative.
- Two conditions of equilibrium:
- Translational equilibrium: \begin{align*}\sum F=F_{net}=0\end{align*}
- Rotational equilibrium: \begin{align*}\sum \tau=\tau_{net}=0\end{align*}

### Image Attributions

**[1]****^**Credit: Charles Hutchins; Source: http://www.flickr.com/photos/celesteh/3266906452/; License: CC BY-NC 3.0

## Description

Covers angular momentum and torque along with translational and rotational equilibrium.

## Difficulty Level:

At Grade## Authors:

## Editors:

## Subjects:

## Date Created:

Dec 05, 2014## Last Modified:

Jun 18, 2015**Save or share your relevant files like activites, homework and worksheet.**

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