# Introduction to SAT II Physics

(Darren Dugan) #1

negative, so E, and not A, is the correct graph.
The answer to question 3 is D. The acceleration due to gravity is constant throughout the ball’s
trajectory, and since it is in a downward direction, its value is negative.
Don’t worry if the question confused you and the explanations didn’t help. This material and more
will be covered in Chapter 2: Kinematics. This was just an exercise to show you how a
classification question is formatted.

#### Part B: Five-Choice Completion Questions

These are the multiple-choice questions we all know and love, and the lifeblood of any multiple-
choice exam. You know the drill: they ask a question, give you five possible answer choices, and
you pick the best one. Got it? Good. An example appears below.
While you’ll often find two or three questions in a row that deal with the same topic in physics,
there is no pattern. You might find a question on modern physics followed by a question on
dynamics followed by a question on optics. However, there is a general tendency for the questions
to become more difficult as you progress.
Five-Choice Completion Question Example

``````D ire cti o ns: E ach o f th e q u est io ns o f i nco mpl e te stat e men ts b e lo w i s fol l owe d by five
sug g e ste d an swe rs o r co mp l et i on s. S el ec t t h e on e th at is be st i n e ach case an d t he n fi ll i n
t he corre sp on d in g oval on t he an swe r sh ee t.``````

1. .A gas in a closed container is steadily heated over a period of time. Which of the following
statements is true of this process?
(A)The average kinetic energy of the gas molecules decreases
(B)The mass of the container increases
(C)The pressure exerted by the gas on the walls of the container increases
(D)The gas changes phase into a liquid
(E)The specific heat of the gas decreases

Explanation
The answer to this question is C. The key lies in remembering the ideal gas law: PV = nRT.
According to this formula, an increase in temperature is accompanied by an increase in pressure. A
is wrong, since the average kinetic energy of gas molecules corresponds to their temperature: if
the temperature increases, so does the average kinetic energy of the molecules. B is wrong because
we’re dealing with a closed container: the mass cannot either increase or decrease. D is wrong
because a gas must be cooled, not heated, to change phase into a liquid. Finally, E is wrong
because the specific heat of any substance is a constant, and not subject to change. We’ll touch on
all this and more in Chapter 9: Thermal Physics.

### How Your Knowledge Will Be Tested

There are three different levels on which your understanding of physics may be tested. While
questions on kinematics often require that you make use of some of the formulas for kinematic
motion, questions on quantum physics or atomic structure may often ask just that you remember
the name of a particular concept. Knowing the different ways in which your knowledge may be
tested should help you better prepare yourself for the exam.