ACT science practice test 25

Directions: Each passage is followed by several questions. After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer document. You may refer to the passages as often as necessary.

You are NOT permitted to use a calculator on this test.


Four basic aerodynamic forces act on an airplane, whether it is a passenger jet or a model made of paper. Thrust is the forward force and drag is the backward force, both of which act parallel to the airplane's motion. Lift is the upward force that acts perpendicular to the airplane's motion. Gravity is the downward force.

Students performed three experiments to determine the effects of different physical modifications on the flying ability of paper airplanes. In each experiment, students used printer paper to create a set of identical paper dart planes. They then modified the airplanes' design to investigate the effect on flight distance.

In each experiment, a single student gently threw each airplane. A second student then measured the horizontal distance covered by each plane. The students performed each experiment three times for each airplane.

Experiment 1

Students created three identical paper airplanes. The first plane's flat wings were left unaltered. The second plane's wings were modified to curve upward in a U shape. The third plane's wings were modified to curve downward in an inverted U shape. The results are shown in Table 1.3.

TABLE 1.3 Airplane Wing Curvature Data

Experiment 2

Students created three identical paper airplanes. They left the first plane's flat wings unaltered. The second plane's wingtips were bent slightly upward. The third plane's wingtips were bent slightly downward. The results are shown in Table 1.4.

TABLE 1.4 Airplane Wingtip Position Data

Experiment 3

Students created four identical paper airplanes. The first plane remained unaltered. Two paperclips were placed on either side of the second plane's nose. Two paperclips were placed on either side of the third plane at midwing. Two paperclips were placed on either side of the fourth plane's tail. The results are shown in Table 1.5.

TABLE 1.5 Airplane Paperclip Position Data

1. Which aerodynamic force is the result of friction as an airplane moves through the air?

A. Thrust
B. Lift
C. Drag
D. Gravity

2. Which pair of aerodynamic forces directly oppose each other?

A. Lift and drag
B. Thrust and lift
C. Gravity and thrust
D. Drag and thrust

3. To keep a paper airplane in the air, the forces of thrust and lift:

A. cannot be less than the forces of drag and gravity.
B. must be equal to each other.
C. cannot be equal to each other.
D. must be less than the forces of drag and gravity.

4. Experiments 1 and 3 differed in the:

A. type of paper used.
B. number of airplanes tested.
C. number of students involved.
D. number of trials performed.

5. Which of the following statements about Experiment 1 is most accurate?

A. Curving the wings slightly upward appears to improve airplane performance.
B. Altering the curvature of the wings appears to have little impact on airplane performance.
C. Curving the wings slightly downward appears to impede airplane performance.
D. Flat wings appear to result in poor airplane performance.

6. In Experiment 2, bending the wingtips slightly downward most likely increased the effect of which force?

A. Drag
B. Lift
C. Thrust
D. Gravity

7. Which condition represents the control group in Experiment 2?

A. Wingtips bent down
B. Wingtips bent up
C. Flat wingtips
D. No wingtips

8. Based on the data from Experiment 3, which paperclip placement had the least effect on flight distance?

A. At the tail
B. On the wingtips
C. At the nose
D. Midwing

9. Based on the data from the three experiments, which of the following is the approximate average horizontal distance traveled by an unaltered airplane?

A. 9.5 m
B. 10.0 m
C. 10.5 m
D. 11.5 m

10. Which modification had the most positive effect on airplane performance?

A. Bending wingtips slightly upward
B. Adding paperclips to the midwing
C. Curving wings upward
D. Bending wingtips slightly downward

11. A student produces the graph shown in Figure 1.2. This graph best represents the data contained in:


Figure 1.2

A. Table 1.3.
B. Table 1.4.
C. Table 1.5.
D. all three tables.

12. An object's center of gravity identifies the average location of the object's weight. In which experiment did students alter the center of gravity of the paper airplanes?

A. All three experiments
B. Experiment 2
C. Experiment 1
D. Experiment 3

13. Which modification changed an airplane's average horizontal distance the most?

A. Adding paperclips to the tail
B. Adding paperclips to the nose
C. Curving wings downward
D. Bending wingtips slightly downward

14. In Table 1.3, the horizontal distance of each individual airplane is shown to increase with each subsequent trial. The most reasonable explanation for this trend is that the:

A. student measuring the distance used different meter sticks with each trial.
B. three airplanes became more aerodynamic with each trial.
C. student throwing increased the amount of initial thrust with each trial.
D. effects of gravity on all three airplanes were decreased with each trial.

15. Based on the data from the three experiments, which combination of features would be expected to produce the longest flight?

A. Wings curved down, flat wingtips, and paperclips at the nose
B. Flat wings, wingtips bent up, and no paperclips
C. Wings curved up, wingtips bent down, and paperclips at the tail
D. Flat wings, flat wingtips, and no paperclips