On Studying
Physics 2325 and 2326
| Dr. Cox | rev. Aug. 2003 |
Many of you, perhaps most, expect to have trouble in a physics class. Many of you (not necessarily the same ones) will have trouble. In many cases this is at least in part because of your study practices. First, the level of effort that got you good grades in high school will generally not be sufficient at the college level; the standards are higher. Furthermore, the study practices that give success in classes such as history or English, or even biology, will not be very effective in physics. This handout will provide some discussion of why and of what may help. You are likely to find that, at first, your studying does not produce the results you aim for; you will have to learn how to "Study smarter, not harder."
Learning what mode of studying is most effective for you is one of the most important things you should gain from college. In the 21st century everyone can expect to be learning new things for their entire life. But effective studying can't be taught in any class, because everyone is different; the most we can do is offer a variety of suggestions for you to try and to compare.
Physics can be described as the study and use of basic principles to solve problems. At the professional level, this can be "pure," research into either new or little-understood phenomena in order to understand what basic principles apply to them; very often such work is as hard to describe as it is to do, because the phenomena involved are unfamiliar. Or it can be "applied," research into how principles we already understand can be used in new situations or new devices. Often these categories blur, as when a "pure" researcher wants to measure something that hasn't been measured before; designing a suitable tool will be applied physics. Or an "applied" researcher has to determine and understand why the new device didn't work quite like the plan; some new phenomena may need to be investigated. In either case, physics is contrasted, at least in principle, with engineering, for which the description is the use of established practices to solve problems. In the real world the distinction may blur, depending on the problems involved; when anything arises that's not covered in "the book," an engineering job turns into physics.
For you as a student, this means that we will try to get you to learn at least some of the basic principles that physicists have developed. They were developed in response to problems, in order to solve future problems. You will see lots of problems; these are not to give you lots of details to learn but so that you can see that a short list of principles can handle a long list of problems - one hopes, even the unpredictable problems that you will some day face, on the job, that your courses (even this one) did not cover. Almost all of your lecture grade will be determined by how well you can do problems in a test situation.
Physics began with simple situations; texts stick mostly to somewhat simplified situations, especially at first. But not everything is simple in the way "common knowledge" would have us think, and some test problems involve cases where "common knowledge" overlooks an important part. Others may test something as simple as distinguishing the physics use of a term from everyday use of it (usually the everyday usage is a looser, less useful meaning).
The purpose of tests is to see if you have learned at least some of what you were supposed to. In this course that learning does not involve straight memorization, it involves understanding of basic principles and especially of how to apply them. The reason physics is required, by most curricula that require it, is that people in that field believe it is important for you to understand these principles and be able to use them in new situations - the situations that were not covered in your courses. The only way to test if you have some degree of that ability is to give you test problems that call for you to apply your knowledge in a new situation, or at least one that is at least somewhat different from those that were previously discussed. Unfortunately this calls for a skill which may not be teachable; the only way I know to develop it is practice, on as varied a problem set as needed. The recommendations in my handouts are only a minimum, intended to be extensive enough to include problems covering all the major topics, without being very repetitive. If you have trouble, repetition with variations may be an answer, and is the reason that most physics textbooks have long, varied, lists of problems. Countering the necessity of a possibly unteachable skill as a requirement for mastery of physics, is the fact that not mastery of that skill, but only some capability with it, is required for progress in physics; since I curve grades, less than 40% of total possible points has been known to be a passing grade.
In this text, as in most physics texts, answers for the odd-numbered problems are in the back: you can determine almost immediately if you agree with them. Caution, however: it is not at all unprecedented for textbooks to have typos even in "well-checked" answer sections. No one but you will evaluate your work on my recommended problems, but they will provide examples for lecture discussion. Test problems should be comparable. If the recommended problems (or others) confuse you, look at the "Discussion Questions"; they will frequently be phrased to bring out the distinctions that students often miss.
I think the approach to learning this material that seems to work for the most students is: read, then work problems, then ASK QUESTIONS. First, read the text, seeing if it seems to make sense. Then read and think about all of the "Discussion Questions" that the author places before the "Exercises." If you understand the material, they should be easy; if you don't see what they're getting at, then you missed something. Now try some "Exercises." If they give you no difficulty, go on to the "Problems", and on through the recommended list. If you want to polish your understanding, try the "Challenge Problems." If a single problem gives you some difficulty, try another before spending a lot of time on one: just a change of context might be enough to let you recognize what you missed on the first try. At whatever point in the above sequence you encounter difficulty, you have identified something to ask about in class. When no one asks questions, the lecture may go smoothly but not as much learning may occur. Rereading before you try problems is probably not going to help you understand: it is the examples and problems that show what the author is talking about, much better than his words alone can.
Redoing a problem, after you have done it once correctly, will probably not help your understanding; it might help somewhat if improved speed is your only goal (but it will help you on speed only if it is not fresh in your mind). Generally a different problem on the same topic will be better.
Quiz/test problems will be mostly story problems and will require thinking; memorizing formulas will certainly not be enough. It may sometimes not be obvious where to start in order to arrive at the required answer, while in many cases information will be provided that seems related but is not actually required. Those are reasons why a variety of practice is recommended, so that you can recognize from previous work which combinations of information can be connected to which other information. On quizzes, each problem will relate primarily to a current topic but may require additional steps based on previous material; on the final the same applies except that the topic and the extra steps can be from any parts.
A useful guideline to keep in mind is that, for each term we introduce, you should know (well enough to use) at least two formulas from which it can be determined. We do not define terms just to have a shorthand for something; this course is too crowded already to allow us to clutter it with additional terms. We define a term, in one way, because we find it useful in some other relationship. For instance, velocity is defined in terms of position and time information, and for some problems that's all you need to find velocity. But we will define both acceleration and, later, momentum, for instance, in terms of velocity, and give you problems to find velocity when there is no position or time information given at all. Frequently, we could have defined our term from the other relationship and derived the original definition instead. In any case, on a test problem the odds probably favor (but not strongly favor) your needing the non-definition relationship to find whatever the unknown is; in real life the odds will likely be no better than even that definitions will be sufficient relationships to find what's needed.
If you have had trouble with math classes, you may have some trouble with the work in this course. On the other hand you might come to realize what that math stuff is good for (because in many cases the math was developed because physics needed it) and thereby finally catch on and understand how to use the math.
If you are looking for more practice, almost any text or study guide labeled Physics, without a subfield modifier, should provide some help. (One labeled Atomic Physics, for instance, won't help.) A book labeled Conceptual Physics will be at a substantially simplified level; one labeled College Physics will be at the level of Physics 1301-1302, using trigonometry but not calculus; while one labeled University Physics, Technical Physics, or Physics for Engineers, or the like, will be calculus-based, at the level of Physics 2325-2326. The lower-level books, or even just a different author's presentation at the same level, may be just what you need to clarify some confusion; and at the least they will have a different set of problems to practice with.
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