generally a bit harder than the one that came before. You should expect questions 11–13 to be
harder than questions 1–4.
Classification Question Example
D ire cti o ns: Each se t of le t te re d cho ice s be l ow ref ers to t he n umb e red q u est i on s
i mme d iat e ly f ol lo wi ng i t. Se l ect th e o ne l et te re d ch oi ce th at b e st an swe rs eac h q ue sti o n
and t he n b lac ke n t he corre sp on d in g sp ace on th e an swe r she e t. A c ho ice may b e use d
o nce , mo re th an on ce, or no t at all i n each se t.
Que st io ns 1– 3
A b oy th row s a bal l st rai g ht u p in t he ai r an d th e n c atch es it ag ai n.
- .Which of the above graphs best represents the ball’s position with respect to time?
- .Which of the above graphs best represents the ball’s velocity with respect to time?
- .Which of the above graphs best represents the ball’s acceleration with respect to time?
Explanation
You can usually answer classification questions a bit more quickly than the standard five-choice
completion questions, since you only need to review one set of answer choices to answer a series
of questions.
The answer to question 1 is B. The ball’s position with respect to time can be expressed by the
equation y = –^1 / 2 gt^2 , where g is the downward, acceleration due to gravity. As we can see, the
graph of y against t is an upside-down parabola. In more intuitive terms, we know that, over time,
a ball thrown in the air will rise, slow down, stop, and then descend.
The answer to question 2 is E. The acceleration due to gravity means that the velocity of the ball
will decrease at a steady rate. On the downward half of the ball’s trajectory, the velocity will be