Read the textbook passage on the next page and then answer the questions that follow by choosing the letter of each correct response.

Question

The “Fourth Law of Motion”: The Automobile Air Bag
A major automobile safety feature is the air bag. Seat belts restrain you so you don’t follow along with Newton’s first law of motion (“An object will remain at rest or in uniform motion in a straight line unless acted on by an external, unbalanced force”) when the car comes to a sudden stop. But where does the air bag come in, and what is its principle?
When a car has a head-on collision with another vehicle or hits an immovable object such as a
tree, it stops almost instantaneously. Even with seat belts, the impact of a head-on collision could be such that seat belts might not restrain you completely, and injuries could occur.
Enter the air bag. This balloon-like bag inflates automatically on hard impact and cushions the
driver. Passenger-side air bags are becoming more common, and back-seat air bags are available.
The air bag tends to “cushion” or increase the contact time in stopping a person, thereby reducing
the impact force (as compared to hitting the dashboard or steering column). Also, the impact force is
spread over a large general area and not applied to certain parts of the body as in the case of seat belts.
Being inquisitive,1 you might wonder what causes an air bag to inflate and what inflates it. Keep
in mind that this must occur in a fraction of a second to do any good. (How much time would there be between the initial collision contact and a driver hitting the steering wheel column?) The air bag’s
inflation is initiated by an electronic sensing unit. This unit contains sensors that detect rapid
decelerations,2 such as those in a high-impact collision. The sensors have threshold settings so that normal hard braking does not activate them, and they are equipped with their own electrical power source because, in a front-end collision, a car’s battery and alternator are among the first things to go.
Sensing an impact, a control unit sends an electric current to an igniter in the air bag system that
sets off a chemical explosion. The gases (mostly nitrogen) rapidly inflate the thin nylon bag. The total
process of sensing to complete inflation takes about 25 thousandths of a second (0.025/s). Pretty fast, and a good thing, too!
However, a recent concern about air bags is the injuries and deaths resulting from their
deployment.3 An air bag is not a soft, fluffy pillow. When activated, it comes out of the dashboard at
speeds of up to 200 miles per hour and could hit a person close by with enough force to cause severe injury and even death. Therefore, adults are advised to sit at least ten inches from the air bag cover. This allows a margin of safety from the two- to three-inch “risk zone.” Seats should be adjusted to allow for the proper safety distance.
Probably a more serious concern is associated with children. Children may get close to the
dashboard if they are not buckled in or not buckled in securely so that they can see. Another bad situation is using a rear-facing child seat in the front passenger seat. An inflating air bag could have serious effects.
Sometimes it may be impossible to follow these safety rules. So air bag deactivation4 may be
authorized for one of four reasons. A rear-facing child restraint might need to be placed in the front seat because the car either has no back seat or has one that is too small. A child 12 years old or younger might need to ride in the front seat because of a medical condition that requires frequent monitoring. An individual who drives (or rides in the front seat) might have a medical condition that would make it safer to have the air bags turned off. A driver might need to sit within a few inches of the air bag (typically because of extremely short stature, 4 feet 6 inches or less).
Specific problems may exist, but air bags save many lives. All new passenger cars must have dual
air bags, and manufacturers are beginning to install air bags that inflate with less force, so as to reduce the possibility of injuries. Even if your car is equipped with air bags, however, always remember to buckle up. (Maybe we should make that Newton’s “fourth law of motion.”)

1. Which of the following sentences best states the thesis of the whole selection?
a. “However, a recent concern about air bags is the injuries and deaths resulting from their deployment.” (paragraph 7)
b. “Specific problems may exist, but air bags save many lives.” (paragraph 10)
c. “A major automobile safety feature is the air bag.” (paragraph 1)
d. “So air bag deactivation may be authorized for one of four reasons.” (paragraph 9)

2. What pattern organizes most of the supporting details in paragraphs 5 and 6?
a. comparison/contrast
b. series
c. time order
d. definition

3. What pattern organizes the supporting details in paragraph 2?
a. comparison/contrast
b. cause/effect
c. time order
d. series

4. Which sentence expresses the main idea in paragraph 8?
a. “Probably a more serious concern is associated with children.”
b. “Children may get close to the dashboard if they are not buckled in or not buckled in securely
so that they can see.”
c. “Another bad situation is using a rear-facing child seat in the front passenger seat.”
d. “An inflating air bag could have serious effects.”

Answer 1

1. b. “Specific problems may exist, but air bags save many lives.” (paragraph 10)
2. b. series
3. b. cause/effect
4. a. “Probably a more serious concern is associated with children.”