Physics 103, General Physics

• Online Textbook Supplement

Announcements:

• The final exam was held Saturday, Jan. 19, and has been graded. Final course grades may be found on BlackBoard.
• A very nice web demonstration of a forced, damped harmonic oscillator can be found at this web site. The factor Q is ω/γ. Note how the resonance amplitude depends on Q, and how the phase of the response is related to the phase of the driving force.

Welcome to Physics 103, General Physics for science and engineering students! I will be teaching the precepts meeting in McDonnell 107 at 9 and 10 AM, which are classes 4 and 9, respectively. The purpose of the course is to understand the basic physics needed for further study in science and engineering, and to develop a logical, quantitative approach to problem solving.

Course Structure

All students in Physics 103 will meet in a big lecture by the course director, Prof. Staggs, every Tuesday. You may consider Tuesday as the beginning of the "course week". On Wednesday, Friday, and Monday, you will separate into groups of approximately 20 students for precepts. Each student should also be registered for a laboratory section. You should expect to put a lot of time into this course, regardless of whether you have studied physics in the past. The structure of the course will encourage you to read and work problems actively throughout the week, which is the key to success.

In the precepts, you will have a chance to discuss the course material and problems in a more interactive setting. The Wednesday class will normally be used to elucidate the concepts presented on Tuesday through conceptual questions and example problems. This is a good time to bring up any questions you may have had about the reading and lecture. The Friday class will be used for working and presenting solutions to in-class problems. To be prepared to participate actively, you should have attempted to work a reasonable amount of Monday's homework before coming to Friday's class. The Monday class will be used used for the final in-class discussion on each topic. It is recommended to come prepared with questions concerning the homework due that night.

Many of you will have previous exposure to physics, perhaps at a rather high level. For others, it may be their first course. Either way, you should expect to learn a lot from this course if you put adequate time into it. Learning physics is iterative - every time you encounter the material, you will find yourself able to go deeper than before, and understand concepts that previously eluded you. I still learn something every time I teach introductory physics, and no one taking this course should assume that it will be easy just because they have "seen it before". Even Einstein made his greatest advances by re-examining ideas at the most fundamental core of Newtonian mechanics, studied and taken for granted by generations of physics students.

It is not unusual for students to come away from a first physics course, particularly at the high school level, with the idea that it has something to do with recognizing equations that have the right symbols in them and then plugging in numbers to solve problems. If this is your present understanding, you can expect a lot of work ahead. Real physics involves recognizing physical concepts in natural situations, modeling them mathematically (often using more geometry than algebra), and finally combining the various relations algebraically to find a solution to the problem. Solving problems by plugging everything into a calculator is only effective for the simplest exercises, and is not an adequate strategy in this course.

Exams

There will be four in-class exams throughout the semester. There will be a final exam scheduled by the registrar for the January exam period. See the syllabus for details. Note that the last few weeks may be subject to change; if so, a new calendar will be posted.

To do well on the exam, you must understand the material at a conceptual level, and know how to set up and work problems based on these concepts. The homework will prepare you for this if you work it thoughtfully. The goal is to be able to generalize what you have learned so that you can apply it in new situations, such as the ones discussed in the Friday classes. Working the problems builds your analytical strength so that you should be able to do this successfully when exam time comes. Just being able to reproduce solutions to problems you have already worked, or seen someone else work, is not a meaningful understanding of physics, and not enough to do well on the exams. The exams are not just about repeating what you have learned in the past. If you think you have understood everything and have done well on the homework, but find the exams very difficult, you may need to put more effort into the set-up stages of the problems, and perhaps work more problems without assistance, so that you will be able to generalize what you learned to new situations.

Partial credit is normally given generously on the exams if you show you know the concepts and make a good attempt at applying them to the situation given. Keep in mind that you must show clearly what you are doing to get credit. If you just try to do all the work numerically and make a mistake, there is no way to tell if you were on the right track, and no grounds for partial credit. A mistake that could have been a trivial deduction if you had shown your work could result in losing most of the credit. Be sure to show the equations you are using, and draw clear and relevant diagrams when applicable. Some words may help if you want to be sure your intention is understood. Remember, exams are all about communicating what you know.

Reading

Each week, you will be given a reading assignment which is correlated with the week's lecture. You should try to do the reading before the lecture, since this will make the lecture much more meaningful. You should consider reading to be a primary means of learning the material (together with working the problems), and an essential part of preparing for meaningful class participation. You simply cannot learn most of what you need to succeed in this course inside the classroom. You will probably find that this is true of every course you are likely to take at Princeton. The goal of reading is deep understanding, not just to extract a list of new vocabulary and equations. Think actively about the examples. Your understanding is enhanced if you reread the material after trying some of the problems, since it will be more meaningful after you have had first-hand experience in applying the concepts. You may find the material in the textbook's online supplement helpful.

Homework

Every week, there will be a short WebAssign homework due on Wednesday night, and a longer one due after the weekend (on Monday night). The purpose of the short homework is to see that you have read the material. The long homework probes your understanding in greater depth. More information on your WebAssign registration will be given to you during lecture on Tuesday. On Fridays, we will have in-class problem sets which are not graded. They will not be posted on BlackBoard, nor emailed; you must come to class on Friday to get them. No solutions will be posted either. These problem sets define the depth of the material we are teaching this semester, and your understanding of them will help you gauge whether you are adequately prepared for the exams.

Some people will find that they need assistance in solving the problem, or find it useful to work in groups. You are encouraged to take advantage of office hours if you would like personal assistance outside of class. Keep in mind that if you come to office hours, I will not work the problems for you, but will try to help you build a more effective strategy. If you work in a group, remember that your group can't help you on an exam. You must know how to solve every problem from the beginning, so that you will develop the skills needed to apply the concepts to new situations. Simply reading another person's solution will not get you to this level. Using someone else's equations without understanding them is a certain route to failure. The more work you can do on your own, the better. No one can learn to solve problems for you. It requires a certain amount of false starts and frustration to develop these skills, so do not give up too easily.

Laboratory

All students must be in a laboratory section and attend every week. If you will miss a lab, you must make arrangements to attend a different session the same week, or present an acceptable excuse. Otherwise you will get a zero that week, because laboratories cannot be made up in a different week. This can reduce your final grade by a full letter. Missing two labs can result in failure. If you added the course late, you will be excused for labs missed before you added it, but they cannot be made up.

Physics 105

Physics 105 will be taught at a somewhat more sophisticated level than Physics 103. The approach of Physics 105 is that of an upper-division physics course, with more emphasis on derivation and the underlying formal structure of physics than one gets in 103. Thus, it will give a better flavor of the more advanced courses in the department, although either course is excellent preparation for further study in physics. If you are primarily interested in applying physics and not very concerned with derivations, 105 would not be your best choice.

All Physics 103 students are eligible to enter 105, regardless of their initial precept section. However, due to the large number of people interested in Physics 105, students who wish to take 105 must follow certain procedures:

• An entrance exam will be given on October 1 from 8-9 PM in McDonnell A02. Admission will be based on this quiz and performance on the homework.
• Students must do the 105 problems each week before the classes separate, in addition to their 103 homework. The problems are posted on the Physics 105 BlackBoard website and turned in to the undergraduate office on the due date. Do not bring 105 problems to me.

Note that the grading in 103 and 105 will follow the same curve (same fraction of As, Bs etc.) regardless of the increased difficulty of 105. Also, students taking 105 will have an extra problem session on Tuesday evenings from 7-midnight.

The primary textbook for Physics 105 is Kleppner and Kolenkow, An Introduction to Mechanics. The first few chapters will be posted on BlackBoard, so that interested students taking 103 need not purchase it immediately. However, if they continue in 105, they will need to purchase it eventually. All students should purchase the Knight text regardless of their intent, since it will be used in parts of 105 as well.

The instructor for Physics 105 is Prof. Page. Additional questions about this course should be addressed to him. Detailed information can be found on his PHY 105 Web Site