1. Today’s Special Turn in paper on front desk HW check/vocab 2
Test results/retake policy
What is the Higgs Boson?
What’s new at NASA this month?
Notes on Motion
In class work

2. Find out who you are and do it on purpose.
Dolly Parton
Fact: Human thigh bones are stronger than concrete.

3. PAe.7: Explain the motion of objects on the basis of Newton’s three laws of motion: inertia; the relationship among force, mass, and acceleration; and action and reaction forces.
PAa.1: Generate hypotheses on the basis of credible, accurate, and relevant sources of scientific information.
PAa.2: Use appropriate laboratory apparatuses, technology, and techniques safely and accurately when conducting a scientific investigation.
PAa.9: Use appropriate safety procedures when conducting investigations.

4. How fast is the butterfly moving? What direction is it moving?
To describe motion, you must state the direction the object is moving as well as how fast the object is moving. You must also tell its location at a certain time.

5. Choosing a Frame of Reference
What is needed to describe motion completely?
A frame of reference is a system of objects that are not moving with respect to one another.
To describe motion accurately and completely, a frame of reference is necessary.

6. Choosing a Frame of Reference
How Fast Are You Moving?
How fast the passengers on a train are moving depends on the frame of reference chosen to measure their motion.
Relative motion is movement in relation to a frame of reference.
As the train moves past a platform, people standing on the platform will see those on the train speeding by.
When the people on the train look at one another, they don’t seem to be moving at all.

7. Measuring Distance
How are distance and displacement different?
Distance is the length of the path between two points. Displacement is the direction from the starting point and the length of a straight line from the starting point to the ending point.

8. Measuring Distance
Distance is the length of a path between two points. When an object moves in a straight line, the distance is the length of the line connecting the object’s starting point and its ending point.
The SI unit for measuring distance is the meter (m).
For very large distances, it is more common to make measurements in kilometers (km).
Distances that are smaller than a meter are measured in centimeters (cm).

9. Measuring Displacements
To describe an object’s position relative to a given point, you need to know how far away and in what direction the object is from that point. Displacement provides this information.

10. Combining Displacements
How do you add displacements?
A vector is a quantity that has magnitude and direction.
Add displacements using vector addition.

11. Combining Displacements Displacement is an example of a vector.
The magnitude can be size, length, or amount.
Arrows on a graph or map are used to represent vectors. The length of the arrow shows the magnitude of the vector.
Vector addition is the combining of vector magnitudes and directions.

12. Combining Displacements
Displacement Along a Straight Line
When two displacements, represented by two vectors, have the same direction, you can add their magnitudes.
If two displacements are in opposite directions, the magnitudes subtract from each other.

13. Combining Displacements
Add the magnitudes of two displacement vectors that have the same direction.
Two displacement vectors with opposite directions are subtracted from each other.

14. Combining Displacements
Displacement That Isn’t Along a Straight Path
When two or more displacement vectors have different directions, they may be combined by graphing.

15. Combining Displacements
Measuring the resultant vector (the diagonal red line) shows that the displacement from the boy’s home to his school is two blocks less than the distance he actually traveled.

16. Combining Displacements
Measuring the resultant vector (the diagonal red line) shows that the displacement from the boy’s home to his school is two blocks less than the distance he actually traveled.

17. Combining Displacements
Measuring the resultant vector (the diagonal red line) shows that the displacement from the boy’s home to his school is two blocks less than the distance he actually traveled.

18. Combining Displacements
Measuring the resultant vector (the diagonal red line) shows that the displacement from the boy’s home to his school is two blocks less than the distance he actually traveled.

19. Combining Displacements
Measuring the resultant vector (the diagonal red line) shows that the displacement from the boy’s home to his school is two blocks less than the distance he actually traveled.

20. Combining Displacements
The boy walked a total distance of 7 blocks. This is the sum of the magnitudes of each vector along the path.
The vector in red is called the resultant vector, which is the vector sum of two or more vectors.
The resultant vector points directly from the starting point to the ending point.

21. Assessment Questions
A car is driving down the highway. From which frame of reference does it appear to not be moving?
standing at the side of the road
a car driving at the same speed but going the opposite direction
sitting inside the car
an airplane flying overhead

22. Assessment Questions
A car is driving down the highway. From which frame of reference does it appear to not be moving?
standing at the side of the road
a car driving at the same speed but going the opposite direction
sitting inside the car
an airplane flying overhead ANS: C

23. Assessment Questions
The SI unit of distance that would be most appropriate for measuring the distance between two cities is the
meter.
centimeter.
kilometer.
mile.

24. Assessment Questions
The SI unit of distance that would be most appropriate for measuring the distance between two cities is the
meter.
centimeter.
kilometer.
mile. ANS: C

25. If you walk across town, taking many turns, your displacement is the
Assessment Questions
If you walk across town, taking many turns, your displacement is the
total distance that you traveled.
distance and direction of a straight line from your starting point to your ending point.
distance in a straight line from your starting point to your ending point.
direction from your starting point to your ending point.

26. If you walk across town, taking many turns, your displacement is the
Assessment Questions
If you walk across town, taking many turns, your displacement is the
total distance that you traveled.
distance and direction of a straight line from your starting point to your ending point.
distance in a straight line from your starting point to your ending point.
direction from your starting point to your ending point. ANS: B

27. Assessment Questions
You travel 30 miles west of your home and then turn around and start going back home. After traveling 10 miles east, what is your displacement from your home?
20 km
20 km west
40 km
40 km west

28. Assessment Questions
You travel 30 miles west of your home and then turn around and start going back home. After traveling 10 miles east, what is your displacement from your home?
20 km
20 km west
40 km
40 km west ANS: B

29. The speed of an in-line skater is usually described in meters per second. The speed of a car is usually described in kilometers per hour.

30. Speed
How are instantaneous speed and average speed different?
Average speed is computed for the entire duration of a trip, and instantaneous speed is measured at a particular instant.

31. Speed
Speed is the ratio of the distance an object moves to the amount of time the object moves.
The SI unit of speed is meters per second (m/s).
Two ways to express the speed of an object are average speed and instantaneous speed.

32. Speed
Average Speed
Sometimes it is useful to know how fast something moves for an entire trip, even though its speed may change during the trip.
Average speed, is the total distance traveled, d, divided by the time, t, it takes to travel that distance.

33. Speed
Calculating Average Speed
While traveling on vacation, you measure the times and distances traveled. You travel 35 kilometers in 0.4 hour, followed by 53 kilometers in 0.6 hour. What is your average speed?

34. Speed
Read and Understand
What information are you given?

35. Total Distance (d) = 35 km + 53 km = 88 km
Speed
Read and Understand
What information are you given?
Total Distance (d) = 35 km + 53 km = 88 km
Total Time (t) = 0.4 h h = 1.0 h

36. Speed
Plan and Solve
What unknown are you trying to calculate?
What formula contains the given quantities and the unknown?
Replace each variable with its known value.

37. Speed
Plan and Solve
What unknown are you trying to calculate?
What formula contains the given quantities and the unknown?
Replace each variable with its known value.

38. Speed
Look Back and Check
Is your answer reasonable?

39. Speed Look Back and Check Is your answer reasonable?
Yes, 88 km/h is a typical highway speed.

40. Speed
1. A person jogs 4.0 kilometers in 32 minutes, then 2.0 kilometers in 22 minutes, and finally 1.0 kilometer in 16 minutes. What is the jogger’s average speed in kilometers per minute?

41. Speed
1. A person jogs 4.0 kilometers in 32 minutes, then 2.0 kilometers in 22 minutes, and finally 1.0 kilometer in 16 minutes. What is the jogger’s average speed in kilometers per minute?
Answer:

42. Speed
2. A train travels 190 kilometers in 3.0 hours, and then 120 kilometers in 2.0 hours. What is its average speed?

43. Speed
2. A train travels 190 kilometers in 3.0 hours, and then 120 kilometers in 2.0 hours. What is its average speed?
Answer:

44. Speed
Instantaneous Speed
Sometimes you need to know how fast you are going at a particular moment.
Instantaneous speed, v, is the rate at which an object is moving at a given moment in time.

45. Speed
The speedometer in a car measures the car’s instantaneous speed.
Note the scale markings are given both in km/h and miles per hour, mph.

46. Graphing Motion
How can you find the speed from a distance-time graph?
The slope of a line on a distance-time graph is speed.

47. Graphing Motion
A distance-time graph is a good way to describe motion.
Slope is the change in the vertical axis value divided by the change in the horizontal axis value.
A steeper slope on a distance-time graph indicates a higher speed.

48. Graphing Motion

49. Graphing Motion

50. Graphing Motion

51. Velocity
How are speed and velocity different?
Velocity is a description of both speed and direction of motion. Velocity is a vector.

52. Velocity
Sometimes knowing only the speed of an object isn’t enough. You also need to know the direction of the object’s motion.
Together, the speed and direction in which an object is moving are called velocity.

53. Velocity
A cheetah’s speed may be as fast as 90 km/h. To describe the cheetah’s velocity, you must also know the direction in which it is moving.

54. Combining Velocities
How do velocities add?
Two or more velocities add by vector addition.

55. Combining Velocities
Sometimes the motion of an object involves more than one velocity.
If a boat is moving on a flowing river, the velocity of the river relative to the riverbank and the velocity of the boat relative to the river combine.
They yield the velocity of the boat relative to the riverbank.

56. Combining Velocities
The velocity of the boat relative to the riverbank is a combination of the relative velocities of the boat and the river.

57. Combining Velocities
The velocity of the boat relative to the riverbank is a combination of the relative velocities of the boat and the river.

58. Assessment Questions
A woman jogs 10 kilometers in one hour, stops at a restaurant for one hour, and then walks 10 kilometers in two hours. What is her average speed for the outing?
0.2 km/h
4 km/h
5 km/h
10 km/h

59. Assessment Questions
A woman jogs 10 kilometers in one hour, stops at a restaurant for one hour, and then walks 10 kilometers in two hours. What is her average speed for the outing?
0.2 km/h
4 km/h
5 km/h
10 km/h ANS: C

60. Assessment Questions
Lisa plotted time on the x-axis of a line graph and distance on the y-axis. What does the slope of her graph represent?
total distance traveled
velocity
speed
displacement

61. Assessment Questions
Lisa plotted time on the x-axis of a line graph and distance on the y-axis. What does the slope of her graph represent?
total distance traveled
velocity
speed
displacement ANS: C

62. Assessment Questions
Lisa plotted time in seconds on the x-axis of a line graph and distance in centimeters on the y-axis. Her plot showed a straight line from (0,0) to (10, 20). What is the speed?
0.5 cm/s
2 cm/s
10 cm/s
20 cm/s

63. Assessment Questions
Lisa plotted time in seconds on the x-axis of a line graph and distance in centimeters on the y-axis. Her plot showed a straight line from (0,0) to (10, 20). What is the speed?
0.5 cm/s
2 cm/s
10 cm/s
20 cm/s ANS: B

64. Two velocities of an object are combined by using
Assessment Questions
Two velocities of an object are combined by using
division of the larger velocity by the smaller velocity.
addition of the two speeds.
vector addition.
numeric addition.

65. Two velocities of an object are combined by using
Assessment Questions
Two velocities of an object are combined by using
division of the larger velocity by the smaller velocity.
addition of the two speeds.
vector addition.
numeric addition. ANS: C

66. Assessment Questions
A kayak is moving across a stream that is flowing downstream at a velocity of 4 km/h. The kayak’s velocity is 3 km/h. What is the magnitude of the kayak’s velocity relative to the river bank?
1.3 km/h
5 km/h
7 km/h
12 km/h

67. Assessment Questions
A kayak is moving across a stream that is flowing downstream at a velocity of 4 km/h. The kayak’s velocity is 3 km/h. What is the magnitude of the kayak’s velocity relative to the river bank?
1.3 km/h
5 km/h
7 km/h
12 km/h ANS: B

68. Assessment Questions
The SI unit for speed of an airplane is miles per hour. True False

69. Assessment Questions
The SI unit for speed of an airplane is miles per hour. True False
ANS: F, kilometers per hour

70. Today’s Special LIAB HW check; Q & A
Grade reminders (retest & homework)
Lab: Investigating free fall (due next time!)
Graphing

71. Homework policy Late homework is not normally accepted
If you did not do you homework/lab on time, and you still want to receive credit, you must go to Homework Club for one full session
Tuesday/Thursday 3:30 to 4:30
You may also receive 2 points extra credit for every Homework Club you attend

72. Bonus video of the day
Formation of the moon

73. Today’s special Turn in lab on front table Interest inventory Theory
Falling object/projectile demo
Notes II
HW II due next time!
Graphing activity

74. The basketball constantly changes velocity as it rises and falls
The basketball constantly changes velocity as it rises and falls. Describing changes in velocity, and how fast they occur, is a part of describing motion.

75. What Is Acceleration?
Changes in Speed
In science, acceleration applies to any change in an object’s velocity.
Acceleration can be caused by positive (increasing) change in speed or by negative (decreasing) change in speed.

76. What Is Acceleration?
Free fall is the movement of an object toward Earth solely because of gravity.
The unit for velocity is meters per second. The unit for acceleration, then, is meters per second per second. This unit is typically written as meters per second squared (m/s2).
Objects falling near Earth’s surface accelerate downward at a rate of 9.8 m/s2 or about 10 m/s2

77. What Is Acceleration?
t = 0 s v = 0 m/s
Each second an object is in free fall, its velocity increases downward by 9.8 meters per second.
The change in the stone’s speed is 9.8 m/s2, the acceleration due to gravity.
t = 1 s v = 9.8 m/s
t = 2 s v = 19.6 m/s
t = 3 s v = 29.4 m/s

78. What Is Acceleration?
A horse on the carousel is traveling at a constant speed, but it is accelerating because its direction is constantly changing.

79. What Is Acceleration?
A roller coaster produces acceleration due to changes in both speed and direction.

80. What Is Acceleration?
Constant acceleration during takeoff results in changes to an aircraft’s velocity that is in a constant direction.

81. Calculating Acceleration
Acceleration is the rate at which velocity changes. Vi is the initial velocity, vf is the final velocity, and t is total time.

82. Calculating Acceleration
A ball rolls down a ramp, starting from rest. After 2 seconds, its velocity is 6 meters per second. What is the acceleration of the ball?

83. Balancing Equations Read and Understand
What information are you given?

84. Balancing Equations Read and Understand
What information are you given?

85. Balancing Equations
Plan and Solve
What unknown are you trying to calculate?
What formula contains the given quantities and the unknown?

86. Balancing Equations
Plan and Solve
What unknown are you trying to calculate?
What formula contains the given quantities and the unknown?

87. Balancing Equations
Plan and Solve
Replace each variable with its known value.

88. Balancing Equations
Plan and Solve
Replace each variable with its known value.

89. Balancing Equations
Look Back and Check
Is your answer reasonable?

90. Balancing Equations Look Back and Check Is your answer reasonable?
Objects in free fall accelerate at a rate of 9.8 m/s2. The ramp is not very steep. An acceleration of 3 m/s2 seems reasonable.

91. Describing Ionic Compounds
1. A car traveling at 10 m/s starts to slow down steadily. It comes to a complete stop in 20 seconds. What is its acceleration?

92. Describing Ionic Compounds
1. A car traveling at 10 m/s starts to decelerate steadily. It comes to a complete stop in 20 seconds. What is its acceleration?
Answer:

93. Describing Ionic Compounds
2. An airplane travels down a runway for 4.0 seconds with an acceleration of 9.0 m/s2. What is its change in velocity during this time?

94. Describing Ionic Compounds
2. An airplane travels down a runway for 4.0 seconds with an acceleration of 9.0 m/s2. What is its change in velocity during this time?
Answer: (vf – vi) = at = (9.0 m/s2)(4.0 s) = 36 m/s

95. Describing Ionic Compounds
3. A child drops a ball from a bridge. The ball strikes the water under the bridge 2.0 seconds later. What is the velocity of the ball when it strikes the water?

96. Describing Ionic Compounds
3. A child drops a ball from a bridge. The ball strikes the water under the bridge 2.0 seconds later. What is the velocity of the ball when it strikes the water?
Answer: vi = 0; vf = at = (9.8 m/s2)(2.0 s) = 20 m/s

97. Describing Ionic Compounds
4. A boy throws a rock straight up into the air. It reaches the highest point of its flight after 2.5 seconds. How fast was the rock going when it left the boy’s hand?

98. Describing Ionic Compounds
4. A boy throws a rock straight up into the air. It reaches the highest point of its flight after 2.5 seconds. How fast was the rock going when it left the boy’s hand?
Answer: vf = 0; vi = –at = –(9.8 m/s2)(2.5 s) = –25 m/s
(The minus sign indicates that the velocity is in the direction opposite the acceleration.)

99. Graphs of Accelerated Motion
The skier’s acceleration is positive. The acceleration is 4 m/s2.

100. Graphs of Accelerated Motion
The biker moves at a constant speed and then slows to a stop.

101. Graphs of Accelerated Motion
A distance-time graph of accelerated motion is a curve. The data in this graph are for a ball dropped from rest toward the ground.

102. Assessment Questions What is acceleration?
the rate at which speed increases
the time an object’s velocity increases
the rate at which displacement changes
the rate at which velocity changes

103. Assessment Questions What is acceleration?
the rate at which speed increases
the time an object’s velocity increases
the rate at which displacement changes
the rate at which velocity changes ANS: D

104. Assessment Questions
A sports car can accelerate from 0 m/s to 28 m/s in four seconds. What is the acceleration of the car?
24 s
7 m/s
27 m/s

105. Assessment Questions
A sports car can accelerate from 0 m/s to 28 m/s in four seconds. What is the acceleration of the car?
24 s
7 m/s
27 m/s
ANS: C

106. Assessment Questions
If you were to sketch a displacement-time graph and a speed-time graph for an object experiencing constant acceleration, what would they look like?
Both graphs would be linear, with the displacement-time graph being steeper.
Both graphs would be linear, with the speed-time graph being steeper.
Both graphs would be nonlinear.
The speed-time graph would be linear; the displacement-time graph would be nonlinear.

107. Assessment Questions
If you were to sketch a displacement-time graph and a speed-time graph for an object experiencing constant acceleration, what would they look like?
Both graphs would be linear, with the displacement-time graph being steeper.
Both graphs would be linear, with the speed-time graph being steeper.
Both graphs would be nonlinear.
The speed-time graph would be linear; the displacement-time graph would be nonlinear. ANS: D

108. Which of the following is an example of negative acceleration?
Assessment Questions
Which of the following is an example of negative acceleration?
Mike starts riding his bike and uses the pedals to go from 0 km/h to 20 km/h.
Mike pedals up a hill and gradually slows from 20 km/h to 5 km/h.
Mike sits on his bike at the top of the hill and rests.
Mike coasts downhill without pedalling, going from 0 km/h to 15 km/h.

109. Which of the following is an example of negative acceleration?
Assessment Questions
Which of the following is an example of negative acceleration?
Mike starts riding his bike and uses the pedals to go from 0 km/h to 20 km/h.
Mike pedals up a hill and gradually slows from 20 km/h to 5 km/h.
Mike sits on his bike at the top of the hill and rests.
Mike coasts downhill without pedalling, going from 0 km/h to 15 km/h. ANS: B

110. The acceleration at a specific point on a distance-time graph is the
Assessment Questions
The acceleration at a specific point on a distance-time graph is the
instantaneous acceleration.
momentary acceleration.
positive acceleration.
numerical acceleration.

111. The acceleration at a specific point on a distance-time graph is the
Assessment Questions
The acceleration at a specific point on a distance-time graph is the
instantaneous acceleration.
momentary acceleration.
positive acceleration.
numerical acceleration. ANS: A

112. Assessment Questions
If an object experiences a steady velocity change in a straight line, it is undergoing constant acceleration. True False

113. Assessment Questions
If an object experiences a steady velocity change in a straight line, it is undergoing constant acceleration. True False
ANS: T

114. Today’s special HW check; Q & A
Secret lives of scientists- Barrington Irving
Practice Test
Lab next
Test 11 next, next time!
Galileo’s experiment

115. Today’s special CERN Trip November 23-25
Lab: Measuring distance & displacement
Test 11 next time!
How to get to mars