1. Table of Contents Chapter 9 Motion and Energy Chapter Preview
9.1 Describing Motion
9.2 Speed and Velocity
9.3 Acceleration
9.4 Energy

2. Chapter Preview Questions
Chapter 9 Motion and Energy
Chapter Preview Questions
1. Is a moving bus a good reference point from which to measure your position?
a. No, because it is often late.
b. No, because it is not a stationary object.
c. Yes, because it is very large.
d. Yes, because it can travel very far.

3. Chapter Preview Questions
Chapter 9 Motion and Energy
Chapter Preview Questions
1. Is a moving bus a good reference point from which to measure your position?
a. No, because it is often late.
b. No, because it is not a stationary object.
c. Yes, because it is very large.
d. Yes, because it can travel very far.

4. Chapter Preview Questions
Chapter 9 Motion and Energy
Chapter Preview Questions
2. To describe a friend’s position with respect to you, you need to know
a. Your friend’s distance from you.
b. The direction your friend is facing.
c. Your friend’s distance and direction from you.
d. Your friend’s distance from a nearby object.

5. Chapter Preview Questions
Chapter 9 Motion and Energy
Chapter Preview Questions
2. To describe a friend’s position with respect to you, you need to know
a. Your friend’s distance from you.
b. The direction your friend is facing.
c. Your friend’s distance and direction from you.
d. Your friend’s distance from a nearby object.

6. Chapter Preview Questions
Chapter 9 Motion and Energy
Chapter Preview Questions
3. Two cars traveling in the same direction pass you at exactly the same time. The car that is going faster
a. moves farther in the same amount of time.
b. has more mass.
c. has the louder engine.
d. has less momentum.

7. Chapter Preview Questions
Chapter 9 Motion and Energy
Chapter Preview Questions
3. Two cars traveling in the same direction pass you at exactly the same time. The car that is going faster
a. moves farther in the same amount of time.
b. has more mass.
c. has the louder engine.
d. has less momentum.

8. Chapter Preview Questions
Chapter 9 Motion and Energy
Chapter Preview Questions
4. To describe an object’s motion, you need to know its
a. position.
b. change in position.
c. distance.
d. change in position over time.

9. Chapter Preview Questions
Chapter 9 Motion and Energy
Chapter Preview Questions
4. To describe an object’s motion, you need to know its
a. position.
b. change in position.
c. distance.
d. change in position over time.

10. Chapter 9 Motion and Energy
How can you describe an object’s motion?
You are in a stationary car and another car passes you. How would you describe the motion of the other car?

11. Chapter 9 Motion and Energy
Use Related Words
Word
Definition
Example Sentence
After investigating the evidence, they concluded that everyone should wear a bicycle helmet.
conclude
v. to decide by reasoning

12. Chapter 9 Motion and Energy
Use Related Words
Word
Definition
Example Sentence
n. a series of numbers and symbols that represents a mathematical rule
formula
The formula for the area of a circle is A = πr2.

13. Chapter 9 Motion and Energy
Use Related Words
Word
Definition
Example Sentence
adj. the possibility that
something will develop
in a certain way
The student who is studying chemistry is a potential chemist.
potential

14. Chapter 9 Motion and Energy
Apply It!
Choose the word from the table that best completes the sentence.
The for finding the area of a rectangle is A = l x w.
formula
2. After waiting for 20 minutes, he that his friend was not coming.
concluded
3. The heavy rains and rising river are a problem for people
who live beside the river.
potential

15. Chapter 9 Motion and Energy
End of Chapter Preview

16. Section 1: Describing Motion
Chapter 9 Motion and Energy
Section 1: Describing Motion
When is an object in motion?
What is the difference between distance and displacement?

17. Relative Motion Chapter 9 Motion and Energy - Describing Motion
Whether or not an object is in motion depends on the reference point you choose.

18. Distance and Displacement
Chapter 9 Motion and Energy
Distance and Displacement
Distance is the total length of the actual path between two points. Displacement is the length and direction of a straight line between starting and ending points.

19. End of Section: Describing Motion
Chapter 9 Motion and Energy
End of Section: Describing Motion

20. Section 2: Speed and Velocity
Chapter 9 Motion and Energy
Section 2: Speed and Velocity
When is an object in motion?
What is the difference between distance and displacement?

21. Calculating Speed Chapter 9 Motion and Energy
If you know the distance an object travels in a certain amount of time, you can calculate the speed of the object.

22. Graphing Motion Chapter 9 Motion and Energy
You can use distance-versus-time graphs to interpret motion.

23. Graphing Motion Activity
Chapter 9 Motion and Energy
Graphing Motion Activity
Click the Active Art button to open a browser window and access Active Art about graphing motion.

24. Click the Video button to watch a movie about velocity.
Chapter 9 Motion and Energy
Velocity
Click the Video button to watch a movie about velocity.

25. End of Section: Speed and Velocity
Chapter 9 Motion and Energy
End of Section: Speed and Velocity

26. Section 3: Acceleration
Chapter 9 Motion and Energy
Section 3: Acceleration
What kind of motion does acceleration refer to?
How do you calculate acceleration?
What graphs can be used to analyze the motion of an accelerating object?

27. Calculating Acceleration
Chapter 9 Motion and Energy
Calculating Acceleration
To determine the acceleration of an object, you must calculate its change in velocity per unit of time.

28. Calculating Acceleration
Chapter 9 Motion and Energy
Calculating Acceleration
As a roller-coaster car starts down a slope, its velocity is 4 m/s. But 3 seconds later, its velocity is 22 m/s in the same direction. What is its acceleration?
Read and Understand
What information have you been given?
Initial velocity = 4 m/s
Final velocity = 22 m/s
Time = 3 s

29. Calculating Acceleration
Chapter 9 Motion and Energy
Calculating Acceleration
As a roller-coaster car starts down a slope, its velocity is 4 m/s. But 3 seconds later, its velocity is 22 m/s in the same direction. What is its acceleration?
Plan and Solve
What quantity are you trying to calculate?
The acceleration of the roller-coaster car = __
What formula contains the given quantities and the unknown quantity?
Acceleration = (Final velocity - Initial velocity)/Time
Perform the calculation.
Acceleration = (22 m/s - 4 m/s)/3 s = 18 m/s/3 s
Acceleration = 6 m/s2
The acceleration is 6 m/s2 down the slope .

30. Calculating Acceleration
Chapter 9 Motion and Energy
Calculating Acceleration
As a roller-coaster car starts down a slope, its velocity is 4 m/s. But 3 seconds later, its velocity is 22 m/s in the same direction. What is its acceleration?
Look Back and Check
Does your answer make sense?
The answer is reasonable. If the car’s velocity increases by 6 m/s each second, its velocity will be 10 m/s after 1 second, 16 m/s after 2 seconds, and 22 m/s after 3 seconds.

31. Calculating Acceleration
Chapter 9 Motion and Energy
Calculating Acceleration
Practice Problem
A falling raindrop accelerates from 10 m/s to 30 m/s in 2 seconds. What is the raindrop’s acceleration?
(30 m/s - 10 m/s) ÷ 2 seconds = 10 m/s2

32. Calculating Acceleration
Chapter 9 Motion and Energy
Calculating Acceleration
Practice Problem
A certain car can accelerate from rest to 27 m/s in 9 seconds. Find the car’s acceleration.
(27 m/s - 0 m/s) ÷ 9 s = 27 m/s ÷ 9 s = 3 m/s2

33. Graphing Acceleration
Chapter 9 Motion and Energy
Graphing Acceleration
You can use both a speed-versus-time graph and a distance-versus-time graph to analyze the motion of an accelerating object.

34. Click the SciLinks button for links on acceleration.
Chapter 9 Motion and Energy
Links on Acceleration
Click the SciLinks button for links on acceleration.

35. End of Section: Acceleration
Chapter 9 Motion and Energy
End of Section: Acceleration

36. Section 4: Energy Chapter 9 Motion and Energy
What factors affect an object’s kinetic energy and potential energy?
How can kinetic energy and potential energy be transformed?
What is the law of conservation of energy?

37. Exponents Chapter 9 Motion and Energy
An exponent tells how many times a number is used as a factor. For example, 3 x 3 can be written as 32. You read this number as “three squared.” In the formula for kinetic energy, speed is squared. For example, you can calculate the kinetic energy of a 70-kg person moving at a speed of 2 m/s by using the formula below.
KE = ½ x Mass x Speed2
= ½ x 70 kg x (2 m/s) 2
= 140 kg•m2/s2 or 140 joules.
Note:
1 kg•m2/s2 = 1 joule

38. Exponents Chapter 9 Motion and Energy
Practice Problem
What is the kinetic energy of a 30-kg rock moving at a speed of 10 m/s?
1,500 joules

39. Kinetic Energy Chapter 9 Motion and Energy
Kinetic energy increases as mass and speed increase.

40. Potential Energy Chapter 9 Motion and Energy
Gravitational potential energy increases as weight and height increase.

41. Transformations Between Potential and Kinetic Energy
Chapter 9 Motion and Energy
Transformations Between Potential and Kinetic Energy
A pendulum continuously transforms energy from kinetic to potential energy and back.

42. Energy Transformations Activity
Chapter 9 Motion and Energy
Energy Transformations Activity
Click the Active Art button to open a browser window and access Active Art about energy transformations.

43. Click the SciLinks button for links on energy.
Chapter 9 Motion and Energy
Links on Energy
Click the SciLinks button for links on energy.

44. Links on Forms of Energy
Chapter 9 Motion and Energy
Links on Forms of Energy
Click the SciLinks button for links on forms of energy.

45. Chapter 9 Motion and Energy
End of Section: Energy

46. Chapter 9 Motion and Energy
QuickTake Quiz
Click to start quiz.