# AT Cycle 20

## 1/10 - 1/13

**T 1/10**

**W 1/11**

**T****h 1/12**

**F 1/13**

### π΄ 2: W 1/11a, π‘ 4: T 1/10 - electrostatics review

Spend the period studying for the exam. Take the time to ask questions and collaborate to solve additional problems.

**Homework**: *Electrostatics Assessment Wednesday, January 11th!* Check out the Circuits Review Videos in preparation for the next unit which we will start Thursday/Friday!!!

To think about the whole unit, here are the **topics in electrostatics** we have studied:

Coulomb's Law

Finding electric field

E = F/q

electric field integral (superposition of dq)

Gauss's Law

Electric potential energy of a configuration of charges

Finding electric potential

potential integral (superposition of dq)

Path integral if we know electric field (compatible with Gauss's Law)

Calculating field and potential due to non-uniform charge distributions (integrals)

You may watch a review video here:

### π₯β 2: W 1/11b, π¨β4: W 1/11 - electrostatics assessment

*Electrostatics Assessment **TODAY!*

**Homework**: Check out the Circuits Review Videos in preparation for the next unit which we will start NEXT CLASS!!! **More Resources for ****equivalent resistance r****eview**: Equivalent resistance is a very useful and fast way of solving circuits with multiple resistors and only one battery. I am assuming you know all about solving series, parallel, and combo circuits using equivalent resistance from last year. If you do not, you may want to review the material by looking at Electrical Circuits Lesson 4 (The Physics Classroom website), or watching videos on Series Circuits and Parallel Circuits (both by Dan Fullerton) and on a Combo Circuit Example (by Ron Call). Remember that the key to success with combo circuits is redrawing every time you combine resistors simply in series or simply in parallel. Work your way forward to find equivalent resistances and then work your way backward to get the currents through and voltage drops across each resistor.

### β€οΈ 2: Th 1/12, π 4: F 1/13a - equivalent resistance, β Positive Physics problems

Today, we'll **review what you should know about circuits from last year**. If you need to review videos from last year, then you can do that. There are several goals today:

To understand the link between electrostatics and circuits.

To understand and know how to use Ohm's Law.

To understand why and how to calculate power lost in a resistor.

To be able to solve simple series and simple parallel circuits with equivalent resistance.

To be able to solve combination circuits with equivalent resistance.

The output is β Positive Physics unit 24: circuit analysis, "challenge 2" work problems only (just 4 problems) due Monday at 10pm. Look on Google Classroom at the bottom of the Classwork page in topic Account Set-up & Tech to see how to set up your β Positive Physics account.

**Homework**: β Positive Physics is due on Monday at 10pm. Make sure you know how to solve circuits with equivalent resistance by then. Only completion score counts, so try the problems till you get them right. **No late work will be accepted!!!** It is best to try to finish these well before they are due because there will be no excuse for late work. Watch the following two videos on Kirchhoff's Laws:

**More Resources**: Equivalent resistance is a very useful and fast way of solving circuits with multiple resistors and only one battery. I am assuming you know all about solving series, parallel, and combo circuits using equivalent resistance from last year. If you do not, you may want to review the material by looking at Electrical Circuits Lesson 4 (The Physics Classroom website), or watching videos on Series Circuits and Parallel Circuits (both by Dan Fullerton) and on a Combo Circuit Example (by Ron Call). Remember that the key to success with combo circuits is redrawing every time you combine resistors simply in series or simply in parallel. Work your way forward to find equivalent resistances and then work your way backward to get the currents through and voltage drops across each resistor.

### π 2: F 1/13, π 4: F 1/13b - Kirchhoff's Laws

Today, we'll review **Kirchhoff's Loop Rule and Junction Rule** by doing an example problem. Although you may have already learned about the technique of using "equivalent resistance," this technique does not work well if we have more than one battery. Kirchhoff's Laws are a much more general technique for solving any circuit. We will be using this technique throughout this unit, so make sure you write down any questions you have and find the answers since it's very important you are an expert in using Kirchhoff's Laws. Pay special attention to sign conventions. Rewatch videos from last post if you need to.

**Homework**: Finish doing Kirchhoff's Laws Intro Problems (New! SOLUTIONS)and write down any questions you might have. Upload solutions to at least 3 of these problems to βοΈ Google Classroom by Monday at 10pm. Also watch the following videos on Capacitors: