Much like Bill Murray in Groundhog Day, those who take many ETS physics tests may develop a feeling of déjà vu...
ETS is many things: creative is not one of them. It uses the same questions over and over and over. Therefore, the best way to study for standardized tests of any kind (especially in physics) is to take lots of practice tests.
A Few Favorite Questions
I can tell you with confidence that the following eight specific questions will show up at least once in a general physics exam by ETS:
1) Block on an inclined plane with friction: find acceleration or coefficient of friction
2) Satellite in circular orbit around a planet: general relationship between two variables such as period and radius, velocity and period, and velocity and radius (Kepler’s laws)
3) Speed at bottom necessary to complete vertical loop
4) Speed as a ball thrown out a window hits the ground
5) Inelastic collision: how much energy is lost (or what is the final velocity)
6) Charged particles in constant magnetic fields (radius dependence on mass, velocity, or magnetic field)
7) Magnetic induction with constant magnetic field for a rod moving along wires at constant speed: relationship between force, speed of rod, resistance in circuit loop
8) Power across resistor (dependence on voltage, resistance)
If I knew the particular exam you were up against, I could tell you even more. For example, if you were taking the SAT II or the AP Physics I exam, I would mention the problems of how velocity of a fluid in a pipe changes with its diameter, what resonant wavelengths are in a half-open pipe, and solving for how much a spring stretches when a weight is hung from it.
How Do I Know?
My familiarity with these exams mainly comes from tutoring. As a physics tutor, I come across a lot of ETS’s past tests, and to be honest, their repetitiveness begins to jump out at you after a while. You can’t completely hack the test this way, but it helps to know that there are certain questions you can complete before even starting the exam. I found out which these questions were, simply by going over past exams with my students.
If you take enough practice tests, you’ll start to notice these questions, yourself— especially if you keep getting them wrong. But whether you have trouble with it or not, any question that shows up (perhaps with very slight variations) on three or more past tests—especially recent ones—is worth some extra attention. Studying these questions in advance will relieve you of some of the time pressure when you actually take the test. In fact, many textbook writers have gotten good at mimicking the standardized tests, so if they keep coming back to a certain question as well, chances are it’s a common one.
Practice Makes Perfect
Of course, it’s important to study the equations and the concepts in preparation for your physics exam, but there is no substitute for taking practice tests. Taking tests is the best way to learn how to take a test—especially once you realize that ETS is completely unimaginative. As a business, it cuts costs by reusing the same question on fifty different exams (thus avoiding having to pay writers more to come up with more questions). Fortunately for you, this means that you will come across the same questions again and again, and can prepare for them.
Finally, knowing which questions are going to come up is useful, but knowing why is even better! These exams are supposed to test knowledge of a wide variety of concepts. ETS’s conception of how to test understanding of a given topic is surprisingly narrow, and the more tests you take, the more you’re going to realize how, exactly, it wants you to understand a given concept. The subject matter may be difficult for you, but when you find out to which sorts of problems the test is restricted, studying becomes a much more efficient affair.