美国高考SATII物理专题分析--SAT II Physics Test-Taking Strategies(2)
Physics Hint 3: Put It on Paper
Don’t be afraid to write and draw compulsively. The first thing you should do once you’ve made sure you understand the question is to draw a diagram of what you’re dealing with. Draw in force vectors, velocity vectors, field lines, ray tracing, or whatever else may be appropriate. Not only will a visual representation relieve some of the pressure on your beleaguered mind, it may also help the solution jump right off the page at you.
Drawing graphs can also make a solution appear out of thin air. Even if a problem doesn’t ask you to express anything in graphic terms, you might find that a rough sketch of, say, the velocity of a particle with respect to time will give you a much clearer sense of what you’re dealing with.
And don’t forget to write down those equations! Writing down all the equations you can think of may lead you to a correct answer even if you don’t really understand the question. Suppose you know the problem deals with an electric circuit, and you’re given values for current and electric potential. Write down equations like V = IR and P = IV, plug in values, fiddle around a little, and see if you can come up with an answer that looks right.
Physics Hint 4: Answers Are Not Convoluted
Remember, on SAT II Physics you’re not allowed to use a calculator, and you’re only given, on average, 48 seconds to answer each question. If you’re working on a problem and find yourself writing out lines and lines of simultaneous equations, trying to figure out 
or trying to recall your trig identities, you’re probably on the wrong track. These questions are designed in such a way that, if you understand what you’re being asked, you will need at most a couple of simple calculations to get the right answer.
Physics Hint 5: Eliminate Wrong Answers
In General Hint 6: Know How To Guess, we explained the virtues of eliminating answers you know to be wrong and taking a guess. On most questions, there will be at least one or two answer choices you can eliminate. There are also certain styles of questions that lend themselves to particular process-of-elimination methods.
Classification Questions
Questions 1–3 relate to the following quantities:
(A) Frequency
(B) Amplitude
(C) Period
(D) Wavelength
(E) Kinetic Energy
1. Which is measured in hertz?
2. For a mass on a spring, which is maximized when the displacement of the mass from its equilibrium position is zero?
3. Which quantity is not applied to pendulum motion?
The weakness of classification questions is that the same five answer choices apply to several questions. Invariably, some of these answer choices will be tempting for some questions but not for others. For instance, you can be pretty sure that kinetic energy isn’t measured in hertz: E may be a tempting answer choice for other questions but not for that one, so you can eliminate it.
Another point that may help you guess in a pinch is that you’ll rarely find that the same answer choice is correct for two different questions. The directions for classification questions explicitly state that an answer choice “may be used once, more than once, or not at all,” but on the whole, the ETS people shy away from the “more than once” possibility. This is by no means a sure bet, but if you’re trying to eliminate answers, you might want to eliminate those choices that you’ve already used on other questions in the same set.