Table of Contents

# Differential Vector Elements

## Prerequisites

Students should be familiar with basic integration and with the $dr$ vector.

## In-class Content

- QUIZ (10 min)
- Small group activity - Boysenberry Patch (20 min)

## Homework for Symmetries

- (Helix)
A helix with 17 turns has height $H$ and radius $R$. Charge is distributed on the helix so that the charge density increases like the square of the distance up the helix. At the bottom of the helix the linear charge density is $0 {\hbox{C}\over\hbox{m}}$. At the top of the helix, the linear charge density is $13 {\hbox{C}\over\hbox{m}}$. What is the total charge on the helix?