AP Central (College Board Site) - AP Physics C Mechanics, AP Physics C E&Mfor use on mock exams in AprilFORMULA SHEET If you need more support for physics basics, go to YouTube and search the topic with one of the following: Khan Academy, vkiledj, or Dan Fullerton (or APlusPhysics). Lesson objectives in Orange. |

### Advanced Topics in Physics

#### How do you know if something is going to tip?

1: F 10/18, 3: Th 10/17Today, we'll talk about tipping problems from Chapter 12 in the textbook. You'll learn how to determine if an object will tip. For tipping problems, you need to really THINK about the situation as you're drawing your free body diagram. You also need to think about the best choice of fulcrum. Finally, using line of action usually helps. Required: Giancoli #38, Halliday #25+, 35, 41, 56 (not really a tipping problem) For #25, also find the force required if the force is applied at the very top of the wheel. Homework: If you haven't finished the problems above, you should finish them for homework. Catch up on any videos you did not watch last week. Next week, there are a lot of homework videos to watch - more than 20 minutes a night. Please get ahead if you can. Watch at least one tonight. QUIZ on static equilibrium (no tipping) next class - Monday, October 21st. |

#### Are ladders really that dangerous?

1: Th 10/17 lab, 3: W 10/16 lab (23 min classes PSAT)Today, we'll start with a short video about ladder safety. We'll use this to generate some questions about ladder safety. We'll use what we know about static equilibrium to figure out where we can stand on a ladder and feel safe. You will work as collaborative team members to build a couple different models of the situation and make predictions about safety. Then, we'll test your Ladder Lab models with a few questions. One of the other groups will test your model and give you feedback. You'll go through the iterative process of engineering your ladder model to correct any weaknesses. You'll answer a few more questions to make sure your model works well. Finally, you'll answer the ultimate question about the real-life safety of ladders by researching some specifications of real ladders and you'll consider some design choices that could make the ladder safer. Handout: Ladder LabHomework: Finish creating your mathematical models on page 1 of Ladder Lab if you have not already done so. We will test your models next time. Watch the following videos on center of mass and tipping. Also, make sure you've finished all the problems in Hard Torque Problems. |

#### When is the line of action method useful in calculating torque?

1: T 10/15, 3: T 10/15QUIZ Today on Archimedes, energy, and momentum.Daily Quiz: line of action method 1. T3 = 250N, m = 40kg 2. T2 = 3700N, Fhy = 2350N down, Fhx = 1850N right 3. T2 = 600N, Fhx = 520N left, Fhy = 50N up 4. T1 = 289N, Fhx = 289N right, Fhy = 350N up 5. Fwall = 727N, Ff = 727N, Fground = 1230N 6. 51.3 degrees (there's a typo, it should say "minimum angle") |

#### What must you consider in doing static equilibrium problems?

1: M 10/14, 3: F 10/11Daily check-in: basic torque and static equilibrium Answers: Hard Torque Problems1. T3 = 250N, m = 40kg 2. T2 = 3700N, Fhy = 2350N down, Fhx = 1850N right 3. T2 = 600N, Fhx = 520N left, Fhy = 50N up 4. T1 = 289N, Fhx = 289N right, Fhy = 350N up 5. Fwall = 727N, Ff = 272N, Fground = 1230N 6. 51.3 degrees (there's a typo, it should say "minimum angle") Homework: Watch the video below. Might be review for some of you.Quiz on Archimedes, work & energy, and momentum next class - Tuesday, October 15th. |

#### How can you find the mass of a meterstick using torque?

1: F 10/11 lab, 3: Th 10/10 labToday, we'll apply the concepts of torque and static equilibrium to find the mass of a meterstick. If you still need help here, watch the following video:Then, we'll work on some simple torque problems. Finish page 1 of the Torque Packet. Handout: Torque Meterstick LabHomework: Finish page 1 of the Torque Packet. Watch the following video on Torque Equilibrium Problems. Also, read the following webpage on Vector Multiplication. Remember that to calculate torque, we use a cross product. Review the right hand rule. Quiz on Archimedes, work & energy, and momentum on Tuesday, October 15th. |

#### How well do you understand momentum?

1: T 10/8, 3: T 10/8Daily check-in: momentum quesitons Today, we'll review momentum by doing the following problems from Chapters 9 to review momentum problems from last year. Support: 18, 22, 39, 58 Required: 32, 38, 42, 44, 48, 59, 117 Enrichment: 20, 69, 83 At the end of class, we'll start the next unit of study. We'll also see a brief demonstration introducing torque.Homework: If you did not finish momentum problems, finish them by the end of the week. There are two videos to watch tonight (total is still under 20 min): Quiz on Archimedes, work & energy, and momentum on Tuesday, October 15th. |

#### How well do you remember energy problems?

1: M 10/7, 3: F 10/4Today, we'll the following problems from Chapters 7 and 8 in Halliday to review energy problems from last year. If you haven't watched the videos from last night, do that first, and follow the steps for making a "before and after diagram" for every energy conservation problem. Support: Ch 7 #32, 36, 45; Ch 8 #19, 21, 36, 52, 55 Required: Ch 7 #30,54, 62, 65; Ch 8 #30, 34, 56, 57, 63, 91 Enrichment: Ch 7 #79; Ch 8 #33, 35, 75, 78 Homework: No Homework Weekend, but if you haven't finish required classwork above, it'd be a good idea to do so, and make sure you've watched the videos from last post. |

#### How can we find the coefficient of kinetic friction with only a meter stick and a balance?

1: F 10/4 lab, 3: Th 10/3 labToday, we'll continue review of last year's material by doing an energy lab. You'll need to find the coefficient of kinetic friction between a wooden block and the lab table. The only measurement devices are a meter stick and a balance. You cannot use any timing devices or motion sensors. You'll focus on work done by a non-conservative force. If you finish early, you should try to find an expression for the coefficient using another method - Newton's Laws. If there's any time remaining, start the problems from the next post.Homework: Make sure your "lab write-up" is in your journal. It's not a formal write-up. Give it a title and make sure you have a labeled diagram of what you measured. Make sure to have some "before-and-after diagrams." Then just your measurements and calculations. |

#### How can you find the density of a mystery liquid?

1: T 10/1 & W 10/2, 3: F 9/27 & W 10/2Today, we're going do a lab. We need to find the density of an unknown liquid. Of course we can do that the traditional way with a graduated cylinder and a balance, but what if we have neither of those things? We'll use Archimedes' Principle and a few basic objects to calculate the unknown density. Homework: Make sure you have completed your write-up for the mystery liquid lab due to Google Classroom Friday, October 4th. Watch below to review how to solve work/energy problems - Giancoli Chapter 8 #27. The important thing in this video is to make sure that you understand how to make a "before & after energy diagram." This method of solving energy problems is not something that is universal amongst physics teachers, but I do think that it is helpful and virtually foolproof, so I would like to see you use it. In addition, you should be able to use the conservation of energy equation to solve energy problems. This method is different than the "Work-Energy Principle" method, so you might want to also look that up in your textbook (p. 153 Halliday) and understand how it differs from the "conservation of energy" method. Both methods work, but given the situation, one usually works better than the other. Figure out why.pre-lab videoFor those of you who are curious, watch the video below about the dot product: |

#### Why do things float or sink?

1: F 9/27 lab, 3: Th 9/26 labDaily Quiz: Basic Archimedes' Principle Today, after your daily quiz on last night's videos, we'll review why things float... you may have learned before that if something is less dense, then it floats. But what are the forces involved? We'll explore Archimedes' Principle which you learned about last night with conceptual examples.Then, we'll work on practice problems from Chapter 14 in order to practice using Archimedes' Principle: Support: 32, 33, 35 Required: 2005B5, 37, 41, 77, Giancoli Ch 13 #32 Enrichment: 43, 48 Make sure you do Giancoli Chapter 13 #32 - "Calculate the true mass (in vacuum) of a piece of aluminum whose apparent mass is 2.0000kg when weighed in air." For the density of air, use 1.29 kg/m ^{3}. For the density of aluminum, use 2.70x10^{3} kg/m^{3}.If there's time, we'll start a lab on Archimedes Principle. Do Halliday Chapter 14 #79 as a pre-lab for next class. Presentation: Archimedes' PrincipleHomework: Review Archimedes' Principle presentation and finish required problems. Do Halliday Chapter 14 #79 as a pre-lab for next class. |

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