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Chapter Review
The motion of an object can be described
and predicted.
CONTENT REVIEW
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KEY CONCEPTS SUMMARY
1
An object in motion changes position.
Position is measured
from a reference point.
VOCABULARY
Motion is measured
relative to an observer.
start
2
position p. 9
reference point p. 10
motion p. 11
finish
Speed measures how fast position changes.
VOCABULARY
• Speed is how fast positions change with time.
• Velocity is speed in a specific direction.
speed p. 16
velocity p. 22
vector p. 22
distance
Speed = time
time
distance
3
Acceleration measures how fast velocity changes.
VOCABULARY
acceleration p. 25
acceleration =
final velocity – initial velocity
time
45
5
initial velocity
34 Unit 1: Motion and Forces
65
85
acceleration
final velocity
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Reviewing Vocabulary
Copy and complete the chart below. If the left
column is blank, give the correct term. If the
right column is blank, give a brief description.
Term
Description
1.
speed in a specific
direction
2.
a change of position
over time
3. speed
4.
an object’s location
5. reference point
6.
the rate at which
velocity changes
over time
7.
a quantity that has
both size and direction
Reviewing Key Concepts
Multiple Choice Choose the letter of
the best answer.
8. A position describes an object’s location
compared to
a. its motion
b. a reference point
c. its speed
d. a vector
9. Maria walked 2 km in half an hour. What
was her average speed during her walk?
a. 1 km/h
b. 2 km/h
c. 4 km/h
d. 6 km/h
10. A vector is a quantity that has
a. speed
b. acceleration
c. size and direction
d. position and distance
11. Mary and Keisha run with the same constant
speed but in opposite directions. The girls have
a. the same position
b. different accelerations
c. different speeds
d. different velocities
12. A swimmer increases her speed as she
approaches the end of the pool. Her
acceleration is
a. in the same direction as her motion
b. in the opposite direction of her motion
c. at right angles to her motion
d. zero
13. A cheetah can go from 0 m/s to 20 m/s in 2 s.
What is the cheetah’s acceleration?
a. 5 m/s2
b. 10 m/s2
c. 20 m/s2
d. 40 m/s2
14. Jon walks for a few minutes, then runs for
a few minutes. During this time, his average
speed is
a. the same as his final speed
b. greater than his final speed
c. less than his final speed
d. zero
15. A car traveling at 40 m/s slows down to
20 m/s. During this time, the car has
a. no acceleration
b. positive acceleration
c. negative acceleration
d. constant velocity
Short Answer Write a short answer to
each question.
16. Suppose you are biking with a friend. How
would your friend describe your relative
motion as he passes you?
17. Describe a situation where an object has a
changing velocity but constant speed.
18. Give two examples of an accelerating object.
Chapter 1: Motion 35
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Thinking Critically
Thinking Critically
Distance North (meters)
Use the following graph to answer the next
three questions.
6
5
A
4
26. CONNECT Describe a frame of reference other
than the ground that you might use to measure
motion. When would you use it?
Using Math Skills in Science
3
2
1
25. APPLY How might a person use a floating stick
to measure the speed at which a river flows?
27. José skated 50 m in 10 s. What was his speed?
B
C
0
1 2 3 4 5
Distance East (meters)
19. OBSERVE Describe the location of point A.
Explain what you used as a reference point
for your location.
20. COMPARE Copy the graph into your notebook.
Draw two different paths an object could take
when moving from point B to point C. How do
the lengths of these two paths compare?
21. ANALYZE An object moves from point A to
point C in the same amount of time that
another object moves from point B to point C.
If both objects traveled in a straight line, which
one had the greater speed?
Read the following paragraph and use the
information to answer the next three questions.
In Aesop’s fable of the tortoise and the hare, a
slow-moving tortoise races a fast-moving hare. The
hare, certain it can win, stops to take a long nap.
Meanwhile, the tortoise continues to move toward
the finish line at a slow but steady speed. When
the hare wakes up, it runs as fast as it can. Just as
the hare is about to catch up to the tortoise,
however, the tortoise wins the race.
22. ANALYZE How does the race between the
tortoise and the hare show the difference
between average speed and instantaneous
speed?
23. MODEL Assume the racetrack was 100 meters
long and the race took 40 minutes. Create
a possible distance-time graph for both the
tortoise and the hare.
24. COMPARE If the racetrack were circular, how
would the tortoise’s speed be different from
its velocity?
36 Unit 1: Motion and Forces
28. Use the information in the photograph below
to calculate the speed of the ant as it moves
down the branch.
0s
10 cm
5s
29. While riding her bicycle, Jamie accelerated
from 7 m/s to 2 m/s in 5 s. What was her
acceleration?
30. PREDICT Look back at the picture at the
beginning of the chapter on pages 6–7.
Predict how the velocity of the roller coaster
will change in the next moment.
31. WRITE A car is traveling east at 40 km/h. Use
this information to predict where the car will
be in one hour. Discuss the assumptions you
made to reach your conclusion and the factors
that might affect it.
If you are doing a unit project, make a folder for
your project. Include in your folder a list of the
resources you will need, the date on which the
project is due, and a schedule to keep track of
your progress. Begin gathering data.
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Standardized Test Practice
For practice on your
state test, go to . . .
TEST PRACTICE
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Interpreting Graphs
The graph below is a distance-time graph showing a 50-meter race.
Distance-Time Graph of Foot Race
50
45
Distance (meters)
40
35
Ashok
Angela
Juanita
Cameron
30
25
20
15
10
5
0
0
1
2
3 4 5 6 7
Time (seconds)
8
9 10
Study the graph and then answer the questions
that follow.
1. Which runner reached the finish line first?
a. Ashok
c. Juanita
b. Angela
d. Cameron
2. How far did Juanita run in the first 4 seconds of
the race?
a. 5 m
c. 25 m
b. 15 m
d. 35 m
3. How much time passed between the time Angela
finished the race and Cameron finished the race?
a. 1 s
c. 3 s
b. 2 s
d. 4 s
4. Which of the following setups would you use to
calculate Angela’s average speed during the race?
50 m
7m
c.
a. 6s
50 s
7s
b. 50 m
50 m
d. 7s
5. What can you say about the speed of all of
the runners?
a. They ran at the same speed.
b. They ran at a steady pace but at different speeds.
c. They sped up as they reached the finish line.
d. They slowed down as they reached the finish line.
Extended Response
Answer the two questions below in detail.
6. Suppose you are biking. What is the difference
between your speed at any given moment during
your bike ride and your average speed for the
entire ride? Which is easier to measure? Why?
7. Suppose you are riding your bike along a path that
is also used by in-line skaters. You pass a skater,
and another biker passes you, both going in the
same direction you’re going. You pass a family
having a picnic on the grass. Describe your motion
from the points of view of the skater, the other
biker, and the family.
Chapter 1: Motion 37