# AP Physics 1 and 2 Combination

#### Course Materials Under Revision for 2017-2018

How to Succeed in Physics:
Science Study Skills

## Physics Student Survival Guide

Or: How to survive a science course, with special attention to the problems of studying physics

#### Why Study Science?

At the heart of all science is something called the scientific method. The simple version of the scientific method is based on the idea that the objective reality of the universe can be determined by carefully observing phenomena, recording appropriate measurements, then studying the data from these observations for patterns that can be used to describe the general behavior of classes of natural objects. When we can control the circumstances of the observations, we are performing experiments, but often we cannot control all the factors before we make observations. There are scientists who believe that the only valid scientific data is that which comes from controlled experiments; in their view, most of astronomy, meteorology, geology, and many parts of biology are not rigorously scientific (but most physics and chemistry are). Since this is a physics course, in most cases we will be working inside the experimental tradition.

Man's search for patterns led him to keep track of many phenomena from very early in recorded history. Heavier items make a deeper dent in the earth when they impact the surface. Some metals, in chips small enough to float on water, will spin round and orient themselves toward the Pole Star. Water, when it turns to steam, expands (it also expands when it turns to ice!). The planets move in complex patterns that repeat only over long periods of time.

When scientists find similarities between objects, or patterns of behavior that repeat with little variation, they want to study the similarities to see if there is some common cause behind them. When the scientist finds a reasonable explanation, he or she proposes a hypothesis, a testable statement about the phenomena. Hypotheses that stand up over many repeated observations are combined to make theories; distillations of theories that have no known exceptions may be called natural laws. In physics, we are particularly concerned with theories of motion (kinematics), force (dynamics), and energy.

#### The Science Course Online

Science classes are frightening for many students. They anticipate difficulties with the concepts, with the details, and especially with the math. But science is just one way of thinking about the natural world around us, and anyone can learn to think like a scientist. Don't waste energy worrying about your ability to learn the material; use your energy to learn it! Once you get the hang of it, you'll be able to discover, understand, and appreciate the complexity of God's creation better. You will also be better prepared to take your place as a steward of that creation.

Review the prerequisites for the course. These are the concepts and math skills that you should have mastered in order to succeed in learning the material. The math prerequisites for this course are described in the FAQs page. If you have any questions about your readiness for the course, be sure to ask for help during our first session. I will arrange to work with you so that you can gain the required skills quickly.

Every science course has as its main components lectures, reading assignments, labs, and lots of homework to prepare you for taking quizzes and exams. In addition to these, our online course has this website, the conference center, and e-mail to provide the functions that would normally exist in talking to your teacher face-to-face, or looking at a bulletin board or whiteboard. Keeping track of all the components can be at daunting task, especially at first, so plan to spend some time becoming familiar with the course website, your text, and the conference center. Once you have mastered the mechanics of using these tools, you can concentrate on learning the material that they contain.

Why are there so many parts to the course? Well, part of the reason is that you learn in many ways. You memorize facts, you comprehend relationships, and eventually, you understand concepts. You learn by reading, by seeing pictures and graphs, by watching demonstrations of processes, by participating in discussions, and by applying what you are learning to specific situations in the homework and labs. You "cement" what you've learned by teaching others. The organization and materials of the course require that you take all these approaches.

#### Managing Your Time

Make the commitment, now, to spend adequate time on coursework. This physics course may challenge you mathematically as well as conceptually, so you must realize right from the start that you cannot do all the work for a given unit on one day ... and you shouldn't do it just before chat session! The table below is a rough guide and a suggested pace for this course. The amount of time you spend on each part of the assigned work will vary greatly from student to student, and your schedule will of course depend on your other commitments. Work out a reasonable work load and stick to it!

Try to do your reading as early as possible. This allows you to think about the questions and material, review it in your mind, and absorb it more critically.

Checklist

 Completed? Task Approximate Time Scheduled for... 1 _____ Check Website for instructions 15 minutes Monday/Wednesday after chat 2 _____ Read Web Lecture 1/2-1 hour Monday/Thursday 3 _____ Read Text Assignment (and work through example problems!) 1-2 hours Monday/Thursday 4 _____ Complete Homework 1-2 hours Wednesday/Friday(Sat) 5 _____ Post assignment to conference center 15 minutes Before class 7 _____ 1-2 hours Before class 7 _____ Make observations for lab 1-2 hours 8 _____ Perform calculations/reduce data 1 hour 9 _____ Write lab report 1 hour 10 _____ Take Moodle quiz 15 minutes (only at the end of the chapter)

#### Web Lectures

Rather than take our precious chat time by lecturing to you, all unit lectures are posted to the site. You need to read these as well as the text. The lecture pages have

• study guide notes to help you with the reading
• a lecture that expands on the text or go into details about related topics
• practice with concepts (checkpoints for your understanding)
• lists of discussion questions to prepare for chat
• a worked homework example
• optional website readings for your copious free time
• link to the associated lab

The "checkpoint" exercises ask you to figure something out, then offer you the opportunity to check your answer. Try to figure things out before hitting the "answer" button! If you were correct, and your reasoning was correct, congratulations! You are ready to continue with the next concept. If you missed the answer, but understand the correction, make a note to review the concept later. If you don't understand the explanation, ask the teacher during class, or send e-mail requesting further help.

As you read the web lecture, make notes on anything that puzzles you, and be sure to raise your questions in class.

#### Getting to Know the Textbook

Read through the Introduction for Giancoli's Physics: Principles with Applications. In particular, note the use of icons and different colors and print conventions (you can skip the acknowledgements sections).

Each chapter has text, graphic materials, and examples. If you have not taken a physical science course before, you may not have run into the use of extensive examples in the text. Sometimes you may figure they aren't worth the time it takes to read them, but don't be misled by this sensation! You should work through every example in the text carefully. Make sure that you understand

• how to interpret the question, so that you know what you are looking for
• how to identify the equation or method to solve the problem
• how to map the information in the question to variables in the equation
• when to convert units, and why
• how to perform the mathematical techniques involved and get a numerically correct answer
• how to figure out the significant figures for the answer

#### Doing Homework

Homework is not merely useful, it is essential for mastering the concepts of a physics course. Just as we test theories by applying them to experimental situations, you test your understanding by applying it to specific situations. You will know whether you understand a concept if you can use it to solve a "real-world" problem, and when you can teach it to someone else.

We use both doing and teaching techniques in this course. You will be assigned calculation problems for each unit. You should work all of these. You will also be asked to post the answer to at least one calculation problem to the course conference center. You will need to show your calculations and explain them in your posted answer.This is your opportunity to help to your fellow students understand a particular situation or problem-solving method.

NB: mycroft, the original bot for my science classes, has long since been freed to do other things, like attend class, make obnoxious remarks, and aid stumped students. If you really get stuck figuring out the problem you've been asked to post, mycroft has been known to accept bribes in the form of virtual Oreo cookies to finish your problem for you.

#### Essay questions

Occasionally, I will assign as homework general questions that don't involve calculation. Essay questions ask you to explain a concept in words. As you answer a science essay question, be prepared to cite calculation information as well as concepts, or give examples.

For example: A projectile has the least speed at which point in its path?

A good answer will be grammatically and syntactically correct, using proper English, as well as contain the correct information. It will cover more than one point in supporting its argument.

Assuming that the projectile is shot at an angle so that it rises with an initial velocity and constantly decelerates under the influence of gravity, it will eventually slow down, stop, and return to the surface. At the top of its arc, its speed will be zero, since it is no longer moving up and has not yet started moving down. This is the point of least speed. [Note that this is not the same as least velocity, which takes direction into account. For least velocity, the answer will depend on what coordinate system is used.]

#### Doing Math Questions

Most physics concepts are really simple. The relationship of velocity, distance, and acceleration can be expressed as


v2 = v02 + 2a(x - x0)



which is relatively simple math. Our problem is in the application of such concepts to real situations.

So here is a "general problem solving" approach.

1. Visualize the situation described. Make sure that you understand what is happening in the real or idealized physical event.
2. Identify all known values listed in the problem, and the unknown to be found.
3. If appropriate, chose a coordinate system that simplifies the math.
4. Set up a notation system for the knowns and unknowns, so that you can use the symbols in math relationships; list the known values and the unknowns.
5. Check for any hidden information — values that you know because of the situation, but which may not be explicitly given in the description. For example, "drop the ball" means that it has a starting or initial velocity of zero.
6. Look for a relationship that relates what you know to what you don't know. You need one equation per unknown value.
7. Solve the formula for the unknown. Don't substitute values in prematurely: you'll only wind up doing more math. Make sure that your units will cancel to give you the correct units for the answer. For example, if you set up a formula to find distance, and the units of the knowns cancel to sec-1, you've done something wrong.
8. Once you have the final version of the formula isolating the unknown and setting it equal to known values, substitute the known values into place.
9. Do the arithmetic.
10. Check your answer for reasonableness, direction, and proper units.

Let's look at an example:

In coming to a stop, a car leaves skid marks 80m on the highway. Assuming a deceleration of 7.00 m/s2, estimate the speed of the car just before braking.

1. Visualize the situation described. Be sure that you understand the concepts involved before you think about how they relate to a mathematical description. Here, visualize what is happening: at some point in time, the driver applies brakes. The car travels 80 meters before it stops. It is decelerating at a constant rate (it doesn't "slow down faster and faster" but slows down steadily).

2. Identify all the "knowns" and the "unknowns". Here we have distance (80m) and deceleration (7.00m/s2). Identify what you want to find out: here it is the speed of the car just before breaking, which will be the magnitude of the velocity at the start of the event. So I am looking for v0.

3. Select a coordinate system. You have vectors, which means direction is important. You must figure out where you are measuring from (an origin point), and how you will measure direction, velocity and acceleration from it. You can set this up any way you like, as long as you are consistent.to simplify the math. For example, you could pick some street corner six blocks away to measure the start and finish displacements from...but then you have to mess around with extra values. It is better to chose the start or end of the deceleration itself -- and useful to note that it doesn't matter which as long as you are consistent through the problem. Since I think of braking the car as a process, I chose the start of the braking as the zero position from which I measure distance.

4. Set up a notation system and list your values. Translate the knowns into mathematical quantities. Here if I decide to measure from the start of the braking, x0 = 0 and x = 80m. If I measure in the direction of travel (velocity is positive going from x0 to x), then deceleration is in the opposite direction, and the acceleration factor a is -7.00m/s2. My list: x0, x, v0, a, and we want to find v.

5. Check for any "hidden" information that isn't explicitly stated. The problem says the car stops, so its final velocity v = 0.

6. Look for a formula that relates most of these together. Of the list on p. 28, the one that only uses factors we know is


v2 = v02 + 2a(x-x0)



7. Isolate the value you want to solve by solving the formula. In this case, we want v0, so we have to rearrange isolate that factor on one side of the equal sign:


v2 - 2a(x-x0) = v02



and then take the square root to get v0:


√ (v2 - 2a(x-x0) ) = v0



8. Substitute the numbers into place:


√ (0 - 2*(-7.00m/s2)(80m -0) ) = v0



9. Solve for the arithmetic answer:


√ ( -2 * -7.00m/s2 * 80m ) = √ (14 * 80 m2/s2) = √ (1120m2/s2) = 33 m/s


10. Double check your work for magnitudes, direction (in the case of vectors) and units.

• Your answer is in terms of dozens of meters, which is consistent the with order of magnitude of the length of the skid marks and the deceleration rate. If you had gotten values of .001 meter or 10000 meters, you would definitely want to redo your calculations.
• Velocity is positive, acceleration was negative. This is consistent with a deceleration situation.
• You were looking for velocity, which is in units of distance/time. m/s is distance/time, so the units work out properly.

#### Getting the Most from Chat

Chat sessions are 90 minutes. Plan accordingly, and take a break just before class starts. Do some stretching, go to the bathroom, eat or get your drinks before you enter the classroom. Be sure to try to connect to your ISP and check mail 10 minutes before class if possible, in case any late notices have been sent by the teacher. Give yourself the extra time. High traffic on your ISP or the school server can slow you down and force you to miss the first 5 to 10 minutes of class.

If you have not already done so, post your assigned questions and answers to the course conference center before the start of class.

Bring your textbook, notes, homework calculations, calculator, and paper and pencil to class. If you are comfortable using a desktop calculator and taking notes in a text utility like Notepad (available as different applications on both Windows and Macintosh), you can use those. Take notes during class. Since Scholars Online logs the chat sessions, you do not need to document things the teacher or other students say, but it is useful to note your own questions and observations as they occur, so that you can study them later.

Take part in the discussion. Ask questions as they occur to you (or note them and ask them at the end of class).

Chat sessions in physics often involve discussion of mathematical calculations. One convention we use is underscore (_) for subscript and up-arrow (^) for superscript. The term x_1 ^2 means "take the value x-sub-1 and square it". You may be more used to seeing this written as x12, and we can actually do that in Dr. Bruce's chat, but it requires a bit of typing. If you prefer to use HTML tags, then here's a quick guide:

• Subscripts are written with the HTML <sub> tag. Be sure to use the closing tag </sub> or you may wind up with material too small to read! The sequence v<sub>0</sub> typed into chat will look like v0.
• Superscripts are written with the HTML <sup> tag. Be sure to use the closing tag </sup> after your exponent or indicator. The sequence 10<sup>3</sup> typed into chat will look like 103.
• You can use unicode to indicate special characters. &alpha; will print as α, frequently used to designate angles. There is a good guide to unicode characters at TNT Luoma HTML Codes.

After chat, log into the chat window again, hit the button for past chat logs, and print the log out. As soon as possible after class, review the log and make notes on it about any points that bother you, and be sure to ask about these in our next session. Mark important points for review later. Consult your notes or the Scholars Online copy of the log to review before the next session and before semester examinations

#### Quizzes

All the physics examinations (quizzes, midterms, and finals) which I use to evaluate your understanding and progress in physics will be drawn from the homework questions in the text and study questions in the workbook. It is very important that you complete the homework problems, study questions, and any reports assigned to prepare for the exams for this course.

There will be an online quiz for each chapter, which will be posted at the quiz site when we have finished discussing the material in the chapter. These quizzes include 10-15 multiple choice questions and are timed. When you take the quiz, you will receive an email copy of the quiz questions, your answers, and your score. In addition, the quiz site will maintain a record of your quiz work, and retain the score of your first attempt.

Most of the questions on the physics midterms and finals which I use to evaluate your understanding and progress in physics will be drawn from the online quizzes and homework. It is very important that you do the homework problems and take the online quizzes to prepare for the exams for this course. The online quizzes will help you prepare for similar questions on the SAT II Physics exam and the AP Physics examination.

#### Exams

Start your review two weeks prior to the scheduled examination.

Read through the chapter highlights at the end of the chapters that will be included in the examination. Make sure that you know the meaning of the boldface terms in the summary.

Go over your homework problems. Use the solutions at the conference center if you cannot redo the problem yourself.

Review the chat logs, and go over your notes.

Review your performance on quizzes, and make a list of the concepts with which you are still unfamiliar or which still puzzle you.

There will be two major exams (semester finals), one in January and one after the last lecture, which you will take during the first week or so in June. These will be mailed electronically to you, and you will take them with your parent or other responsible adult as proctor, and e-mail your answers back to me. Both exams contain a large multiple choice section with questions drawn from the online quizzes, and math-type problems similar to our homework problems. Both sections will be closed-book. You may bring to these exams one 8.5 x 11 inch sheet of paper with whatever notes on it that you desire — so don't worry about memorizing formula. Learn concepts and applications!

#### Study Groups

Not only may you study together, but you should study together — remember that explaining or teaching what you just learned to someone else is one of the important techniques of learning! You may also work together to solve the homework problems ... but be sure that you can solve them on your own afterwards, since you cannot work as a study group on quizzes or examinations. You may use the general class forum (accessible from the top section of the Physics Moodle page) to start discussion threads for asynchronous meetings.

#### Doing Labs: The Scientific Experience

One of the basic methods of science is to secure documented observations of periodic or common events in order to make some general summary about the behavior of natural objects. We can do this in several ways.

• Directed observation

All observations of stars and planets, most observations of plants and animals in their native habitats, and many observations of geological specimens and meteorological events, are "field" observations. The situations must be allowed to occur without human direction, either because such direction is impossible (we can't control when a star will go nova), or because human intervention would interfer with the observation (we don't want to feed animals if we are researching their eating habits in the wild). The best we can do is make many observations of phenomena that are as similar as possible.

• Laboratory-based experiments

Laboratory-based observations are much more tightly controlled. Specific techniques and equipment are used for particular kinds of data collection. The experimenter can often vary only one factor at a time to see how it affects other dependencies. This allows many experimentalists to compare their results easily.

• Surveys

Frequently, research in one area reveals a tendency for a particular phenomena\on to behave a certain way. Rather than simply starting to observe the phenomena anew, one may choose to go back through past observations, looking for the same patterns or evidence of how nature behaved in similar circumstances. Surveys of historical data are common in weather studies, where such records exist for periods of 100 to 150 years, and in astronomical observations.

Surveys and re-examination of astronomical data are very common, since telescope plates taken in the 1920s by a researcher interested in a single star or event will contain data relevant to other events as well. The earliest photograph showing the growing magnitude due to the supernova of 1987 was taken by an Australian astronomer who was looking for something else entirely in a different part of the Magellanic Cloud. After checking the photo for his own star, he went to bed...and so missed being the "discoverer".

### Special concerns for Physics Labs

Writing Lab Reports

Your lab report is the evidence of your observations of a particular phenomena. Your observations should be presented in such a way that the data is easy to understand and supports your conclusions, but also with enough detail on how you obtained them that any peer with similar equipment could repeat your experience and confirm your results (or challenge them, as the case may be).

Organization: A good science lab report has at least seven sections:

1. The abstract: a short paragraph explaining the goal of the lab, the overall purpose or hypothesis, the type of data gathered, and the conclusions.
2. Materials and equipment: a description of the consumable materials and the observing equipment, instruments used to collect data. For standard equipment, references to the make and model are generally sufficient, along with verification that the equipment was tested for proper calibration.. If the equipment was modified, or specially configured, describe the new settings. If the equipment was specially built, either summarize the intent and purpose of the equipment and methods of calibration, or refer to other documents which provide this information.
3. Procedure: a list of steps taken to secure the data. This should be detailed enough to allow peers in the field to repeat the measurements you made under simillar circumstances. Any choices you made that might affect results should be stated, along with the reasons you made them.
4. Raw Data: the numbers you copied from instruments, descriptions of what you saw with your own eys, notes to yourself about odd things that happened, and rough sketches made during the observation. They might also include photographs, data collected by computer, and so forth. In many cases, the amount of data collected this way exceeds the space available in a formal report, so you do not need to include all of it. You should select representative samples of this data, and retain your notebooks with the actual raw data for reference if anyone questions your results.
5. Sample Calculations: at least one each of any calculations you did to determine reliability (statistical analyses) or to figure out derived data (e.g., density from volume and mass measurements). This allows a reviewer (such as your teacher) to determine whether you used the proper technique of data reduction in this situation.
6. Processed Data: all the processed data on which you base your results in the most useful forms. Frequently this involves creating a table, and may additionally involve preparing graphs to show trends.
7. Conclusions: your assessment of whether your originaly hypothesis or assumptions are supported by actual phenomena. If your results did not bear out your assumptions, but you still feel the assumption is correct, you should explain the source of the problem (errors in measurement, calculations, equipment), and outline a plan for redoing the observations. When your experiment bears out your hypothesis, your conclusion should place these results in the context of the large field, and could include suggestions for further research.

Resources

Obviously...

Check "PHYSICS" at the Google Search site for current areas of physics and astronomy (which is mostly physics!) interest on the Web.

Current events....

Major upsets in theory show up in news reports from time to time; a good source for these will be the "Science" section of news.google.com or the Yahoo news page.

Course wares...

Physics isn't the most popular science, but it does lend itself to modeling, something computers are really good at. We'll take advantage of the many simulations available on the web.

CourseInfoLessons [Enrolled Students]