Day 1. Agenda: Review of velocity, acceleration & force Vectors WS Begin Defining Newton s Laws. Do Now: Go Formative-- Intro To Forces

Transcription

1 Day 1 Agenda: Review of velocity, acceleration & force Vectors WS Begin Defining Newton s Laws Do Now: Go Formative-- Intro To Forces New Unit Interaction & Forces Due Today Semester 1 Reflection Due Next Class Vectors WS 1

2 Physics Review Use your Physics Binder as a reference tool to define the terms below in your new Toolbox. Velocity Acceleration Force Interaction 2

3 Vectors Worksheet Vector: The world s greatest super-villain A mathematical term represented by an arrow, with both a direction and magnitude OH YEAH! 3

4 Net Force and Equilibrium Net Force: The sum of all force vectors acting on an object Equilibrium: A system is in equilibrium if the forces are balanced. (FNet= 0 N) 4

5 Vectors Worksheet Example: Each square represents a force of ONE NEWTON. This vector shows a 5 N force to the right. Magnitude = 5 N Direction = Right Finish Questions 1 and 2 of Packet 5

6 Vector Addition More than one force can act on an object at the same time. The first vector has shows a force of 5 N to the right. The second vector has shows a force of 3 N to the right. FNET (Resultant) The sum of these 2 vectors would be 8 N to the right. 6

7 Vector Addition Forces acting in opposite directions The first vector has shows a force of 5 N to the right. The second vector has shows a force of 3 N to the left. FNET (Resultant) The sum of these 2 vectors would be 2 N to the right. 7

8 Finish Question 3 of Packet Do not continue on to question 4 8

9 Newton s Laws Newton s 1st Law: Newton s 2nd Law: Newton s 3rd Law: (not yet!) 9

10 Forces 10

11 Forces Balanced Unbalanced FNet 0 FNet = 0 Objects in motion stay in motion. Objects at rest stay at rest Constant Velocity v=0 At Rest v 0 When there is an unbalanced force, things accelerate Constant change in motion (acceleration) FNet in direction of motion Constant Motion Speeding up FNet in opposite direction as motion Slowing down 11

12 Forces Balanced Unbalanced FNet = 0 FNet 0 When there is an unbalanced force, things accelerate Objects in motion stay in motion. Objects at rest stay at rest Constant Velocity v=0 At Rest v 0 Constant change in motion (acceleration) FNet in direction of motion Constant Motion Speeding up FNet in opposite direction as motion Slowing down 12

13 Now use your flowchart to finish the Vectors WS 13

14 14

15 Day 2 Agenda: Pushy-Joe Simulation & Data Collection Do Now: What happens when forces are balanced on an object? What happens when forces are unbalanced on an object? Due Today Vectors Worksheet Due Next Class Pushy Joe 15

16 Pushy Joe Activity Whatever Angie comes up with :) 16

17 Pushy Joe Lab Groups: A: Girl B: Bucket of Water C: Girl holding the Crate D: Dude sitting on the Crate 17

18 Pushy Joe Lab Wild Guess: What is the acceleration of your object when FNet= 500 N? Physics FP Intro to Energy + Engineering a Wind Turbine 18

19 Pushy Joe Lab Research Question: How does the Net Force acting on an object affect its acceleration? Physics FP Intro to Energy + Engineering a Wind Turbine 19

20 Pushy Joe Lab Variables: 1. Identify the independent variables. 2. Identify the dependent variables. 3. Identify the controlled variables. Physics FP Intro to Energy + Engineering a Wind Turbine 20

21 Pushy Joe Lab Net Force Hypothesis: Acceleration 1) Sketch in graph form 2) In words I think Net Force depends on Acceleration in a relationship Physics FP Intro to Energy + Engineering a Wind Turbine 21

22 Pushy Joe Lab Method: 1. Procedure 2. How will you change the independent variables? 3. How will you control the controlled variables? Physics FP Intro to Energy + Engineering a Wind Turbine 22

23 Pushy Joe Lab Data Collection Physics FP Intro to Energy + Engineering a Wind Turbine 23

24 Pushy Joe Lab Use Desmos.com to graph your data and determine the equation of the best-fit line. Remember to use the Lincoln Start-up File Re-create your graph on the class-agreed scale 24

25 Pushy Joe Lab Write a 5-step Conclusion to the lab. Remember to use your own equation and your own mass for your data-informed prediction and confidence. Use your Physics Binder as a resource/ reminder! 25

26 26

27 Measuring Forces Activity 1. Complete the Prediction boxes for each scenario. 2. Show Mr. Hill complete boxes to get 2 spring scales. 3. Make measurements in Newtons (N). Anchor Scenarios need exemplar to stay up 27

28 If Time Allows: Mini-Lab Prediction: How much 600 g will weigh? Research Question: How is mass related to weight? 28

29 By the End of Class You Should Content Objective Be able to identify balanced and unbalanced forces. Language Objective Be able to use words and arrows to describe forces. 29

30 Cover Homework Rd 2.1 & 2.2 Q: 1,3,6,8,22,27 30

31 Making Sense of Measuring Forces Activity 1. If an object doesn t move what must be true about all the forces on the object? 2. In situation #5 you pulled 1 N and found the max force of friction to around 1 N, then in situation #6 you pulled 0.5 N, what can we infer about how hard friction resisted the motion in this case? 3. Big Idea: friction only pulls back as hard as you pull, up until it maxes out. Then it just pulls its maximum 31

32 Throwing Book on Table vs. Skateboard InteractionIf table pulls book (slowing it down); book must push on table. Is this true? 32

33 Graphs Help Us See Patterns So let s graph how objects moved based on the strength of their interaction with another object Object Strength of Interaction Sticky Book with lots of duct tape Very Strong Sticky Book with little duct tape Strong Sticky Residue from tape Pretty Strong Smooth Book Medium On Pens Little 33

34 Let s get active! Super Strong Friction (a lot of tape) High Friction (a little tape) Medium Friction (a little masking tape) Low Friction (just book) Tiny Friction (book on pens) No Friction (imagine) Distance object rolls Force Needed to Keep It Moving 34

35 Title these graphs, regarding their Big Ideas It is natural to keep moving, friction is what makes thing stop Friction slows things down Super Strong Friction High Friction Medium Friction Low Friction Tiny Friction No Friction Distance object rolls Force Needed to Keep It Moving 35

36 Things in motion seem to stay in motion! It is the force of friction that slows things down. Super Sticky Friction High Sticky Friction Medium Friction Low Friction Tiny Friction Distance roll Force Needed to Keep Moving 36

37 We Call This Property of Things Inertia 37

38 Key Vocabulary Inertia: The property of all things to continue their motion until acted upon by a total force. 38

39 Making Sense of Measuring Forces Activity 1. If an object doesn t move what must be true about all the forces on the object? 2. In situation #5 you pulled 1 N and found the max force of friction to around 1 N, then in situation #6 you pulled 0.5 N, what can we infer about how hard friction resisted the motion in this case? 3. Big Idea: friction only pulls back as hard as you pull, up until it maxes out. Then it just pulls its maximum 4. How can you achieve situation #10? 39

40 Key Vocabulary Net Force: The total force on an object. Equilibrium: all forces are balanced. Total force or Net Force is zero. 40

41 SQPRRS 2.3 & 2.4 Survey Question Predict Read Respond Summarize 41

42 Day 3 Physics - Mr. Hill Agenda: Finding Patterns in Force through Data Mining Skywork Question: Scientist often utilize data that someone else already collected to answer their own new question For example: Describe or Upcoming Events Read Mining Google searches for drug side Due Next Class Packet Page 5 effects Due Today Rd 2.3 & 2.4, Q: 24-27: 14,15,23,26,27 42

43 Cover Homework Rd 2.3 & 2.4, Q: 24-27: 14,15,23,26,27 43

44 By the End of Class You Should Content Objective Be to evaluate a pre existing data set for its usefulness to answer your question. Language Objective Be able to discuss a pattern with supporting evidence. 44

45 Experimenting on the Effect of Unbalanced Forces Wild Guess: How far will the ball bearing roll from the ramp if the force of friction on the ball from the carpet is N. Research Question: Next slide, depends on what group you are in. 45

46 Experimenting on the Effect of Unbalanced Forces Group A how does the Applied Force change the motion of a ball? Group B how does the Friction Force change the motion of a ball? Group 1 How does an unbalanced total force affect acceleration? Group 2 How does the mass affect acceleration? Group C how does the speed change the effect of the total force on the motion? 46

47 Ramping Up our Hypothesis Hypothesis: acceleration Your Parameter (Fa, Ff, Ftotal, mass, speed) 1) sketch in graph form (think about one set-up from previous slide than think doubling or halving the width) 2) in words I think the affects the acceleration in a relationship, this makes sense because 47

48 Experimenting on the Effect of Unbalanced Forces Variables: 1. identify the independent variables 2. identify the dependent variables 3. Identify the controlled variables 48

49 Find File at Method: 1. Open Data File and Orientate Yourself Scan headings Total Force needs attention (equation, error, ) What kind of carpet What kind of balls are these 49

50 Experimenting on the Effect of Unbalanced Forces Value of controlled variables: Force of Push on Mass of Surface Ball Ball (kg) (N) +/0.2 Carpet Carpet Carpet Carpet Carpet Starting Speed of the Change in Speed Change in Force of Total Speed of the Ball after 10 of the Ball over Speed of the Friction on Force on Ball Seconds 10 Seconds Ball over 1 Ball Ball (MPH) +/(MPH) +/- (MPH/(10 s)) +/Second (N) +/- 0.2 (N) (MPH/s) +/ Change in Force of Starting Change in Speed of the Force of Total Mass of Push on Speed of Speed of the Ball Speed of the Ball over 10 Friction on Force on Surface Ball Ball the Ball after 10 Seconds Ball over 1 Seconds Ball Ball (kg) (N) +/(MPH) +/(MPH) +/- 0.3 Second (MPH/(10 s)) (N) +/- 0.2 (N) (MPH/s) +/- 1 +/- 1 Carpet Carpet Carpet

51 Graph of Good Data 51

52 Graph of Good Data 52

53 Graph of Good Data 53

54 Board Meeting Making Sense of all this Data 1. Let s orient ourselves to these graphs. 2. Let s start with acceleration vs mass What is the pattern? Why does this make sense? Where did the constant 4.9 come from? Why does this make sense? 3. What is going on in the acceleration vs total force graph? 54

55 Experimenting with Effect of Unbalanced Forces 55

56 Experimenting on the Effect of Unbalanced Forces + 56

57 Note on Scientific Language 57

58 Conclusion: Since the best-fit line of all our data is, I conclude that there is a relationship between the acceleration and. This can be represented mathematically: So I predict through using computational reasoning that withnext a force Slide of friction of N, the ball will roll m on the carpet. My confidence is because. 58

59 Computation Reasoning with Excel to get Prediction Create a motion data table (t, x, v, a) Put in a from wild guess and pattern with force. Create dummy time intervals Set and drag equations for v and x Then look for where ball stops Then read x for that condition 59

60 Test Prediction I get what Mr. Hill means when he says we take some measurements about how much friction there is when you change the surface or how hard to press the surfaces together, apply some mathematics to find a pattern, and than we can predict the amount of friction there will be in a new case involving the same surfaces. 60

61 Prediction Draw ramp, ball, and carpet and work from this drawing. 61

62 Test Prediction Science works! We can find a pattern in nature and use it to accurately predict the future. Wild guess sometimes close, sometimes not. How do you know which of these it is? With careful investigation we can predict the future again and again with some level of confidence. 62

63 Monday, January 7th Physics - Mr. Hill Agenda: Day 4 Finish Experiment on Effect of Forces Reasoning about s Balanced vs Unbalanced Skywork Question: 1. What happens when forces are balance on an object? 2. What happens when forces on unbalanced on an object. Upcoming Next Friday Due Next Class Packet Page 2 (except for Ff) & 6 Due Today Packet Page 5 63

64 By the End of Class You Should Content Objective Have a working understanding of the role of Inquiry & into Science. Language Objective Be able to discuss a pattern with supporting evidence. 64

65 Cover Pages 5 65

66 Finish Data Mining to Find Newton s Second Law 66

67 How do we complete this chart? Forces Balanced Unbalanced Ftotal = 0 Ftotal 0 When you really push, Objects in motion tend to stay in motion. Objects at rest tend to stay at rest things accelerate? Acceleration? Constant Velocity v=0 At Rest v 0 Ftotal in direction of motion Constant Motion Speeding up Ftotal in opposite direction as motion Slowing down 67

68 Put in Toolbox Physics 1 Inquiry & Patterns 2 Motion & Energy 3 Interaction & Forces 4 Energy & Interactions SI Scientific Inquiry Fold Here EP Engineering Projects 68

69 Forces Balanced Unbalanced Fnet = 0 Fnet 0 When you really push, Objects in motion tend to stay in motion. Objects at rest tend to stay at rest Constant Velocity v=0 At Rest v 0 things accelerate Constant Acceleration Fnet in direction of motion Constant Motion Speeding up Fnet in opposite direction as motion Slowing down 69

70 Key Vocabulary Newton s Second Law: Acceleration depends on both the total force and the mass of the object 70

71 Acceleration vs Net Force Pattern: Linear so when F and when F F, a a F, a a 4 When Force is doubled, 2 acceleration is doubled

72 Acceleration vs Mass Pattern: Inverse so when m and when m m, a m, a a a When mass is doubled, acceleration will decrease by half

73 Begin Packet 2, 6 73

74 Day 5 Physics - Mr. Hill Agenda: Reasoning about Forces Using Force Analysis to solve problems SQPRRS Skywork Question: Can there be an interaction with a single object? Upcoming Next Week Short Answer Quiz on Forces Due Today Packet Page 2 (except for Ff) & 6 Due Next Class Rd Q s: 1,2,5,6,21,22,23,31,33 74

75 By the End of Class You Should Content Objective You should be able to distinguish between forces within an interaction and multiple forces on a single object. Language Objective Be able to use accurately use force pairs and total force to describe physical scenarios. 75

76 Key Vocabulary Newton s Third Law: Forces comes in pairs 76

77 Table pushes pencil Pencil pushes table 77

78 Earth pulls weight Weight pulls 78

79 Weight pulls string String pulls 79

80 Air pushes blade Blade pushes 80

81 Person pushes down on log Log pushes up on 81

82 Log pushes down on cliff Cliff pushes up on 82

83 A B Person A pulls on metal Metal pulls on Person B pulls on metal Metal pulls on 83

84 A B Person A pushes metal Metal pushes Person B pushes metal Metal pushes 84

85 Cover Page 2 & 6 85

86 Reasoning about s Anchor Scenarios - need on poster paper to stay up Explaining through cartoons these three scenarios with a cyclist: 1. Cyclist pedals kind of strong to go a constant 10 mph. 2. Cyclist pedals super strong to speed up to 25 mph. 3. Cyclist then has to pedal medium strong just to stay going a constant 25 mph. Visually: scene, Fpedal, Fair resistance, Fnet, Balance/Unbalanced + 1 sentence reasoning 86

87 Analyzing Surprising Situations with Forces Erin says Mr. Hill that stuff about interaction can t be right. When I drop a basketball it falls to the earth, the earth doesn t also fall towards the basketball. Think. Pair. Share. Write. Need on poster paper to stay up Mass of Basketball 0.6 kg Mass of Earth kg Force of interaction on each other W = mg = 6 N What impact will that have in changing each of their motions? What sort of acceleration is involve for each? What about of time is the change happening for? What will be the net movement of each in this time? 87

88 SQPRRS On Whiteboards Survey Question Predict Read Respond Summarize Due Tomorrow Rd Q s: 1,2,5,6,21,22,23,31,33 88

89 Check In: You Should Content Objective You should be able to distinguish between forces within an interaction and multiple forces on a single object. Language Objective Be able to use accurately use force pairs and total force to describe physical scenarios. 89

90 Day 6 Physics - Mr. Hill Agenda: Cover Homework Using Force Analysis to solve problems Experimenting with Friction Skywork Question: How could we make the frictional force between a book and the table bigger? Upcoming Next Week Short Answer Quiz on Forces Due Next Class Packet Page 7 Due Today Rd Q s: 1,2,5,6,21,22,23,31,33 90

91 By the End of Class You Should Content Objective Have a working understanding of patterns with friction Language Objective Be able to discuss the patterns friction using supporting evidence. 91

92 Cover Homework Rd Q s: 1,2,5,6,21,22,23,31,33 92

93 In an experiment, you use a spring scale to pull a 0.5 kg wood block. You observe the block does not move at first, even when you pull with 2.0 N of force. Immediately after pulling the slightest bit harder the block begins to accelerate. 93

94 a a Fapplied Fnet 94

95 Connecting to These Scenarios Need on poster paper to stay up Make your cartoons quantitative for the three scenarios with a cyclist: 1. Cyclist pedals kind of strong to go a constant 10 mph. 2. Cyclist pedals super strong to speed up to 25 mph. 3. Cyclist then has to pedal medium strong just to stay going a constant 25 mph. Visually: scene, Fpedal, Fair resistance, Fnet, Balance/Unbalanced + 1 sentence reasoning 95

96 Experimenting with the Force of Friction Wild Guess: How hard will you have to pull 6 Physics Text Books to keep them moving if they are stacked on top of 10 round pens that are on the table? Research Question: How do surfaces and amount of force the surfaces are pressed together affect friction? 96

97 Experimenting with the Force of Friction Group A: How does the strength of friction for a book on table top depend on how hard the book and tabletop are pressed together? Group B: How does the strength friction for a book on pens depend on how hard the book and pens are pressed together? Group C: How does the strength of friction to start a book on table top moving depend on how hard the book and tabletop are pressed together? 97

98 Experimenting with the Force of Friction Hypothesis: Force of Friction Ff 2 lines: 1 for book on table 1 for book on pens 1 for book stuck on table Force pressed together (weight) 1) Sketch in graph form (think about one set-up from previous slide than think doubling or halving the width) 2) In words I think the force pressed together affects the force of friction in a relationship 98

99 Experimenting with the Force of Friction Variables: 1. Identify the independent variables 2. Identify the dependent variables 3. Identify the controlled variables 99

100 Experimenting with the Force of Friction Method: 1. Experimental set-up 2. How will you change the independent variables? 3. How will you control the controlled variables? 100

101 Experimenting with the Force of Friction Value of controlled variables: g = 10 m/s2 ; book = N Force Pressed Together (N) +/- Force of Friction (N) +/- if books stays at constant velocity Trial 1 Trial 2 Average Friction (N) Uncertainty in Friction (N) Trial

102 Experimenting with the Force of Friction Friction (N) What is this? Force Pressed Together (N) 102

103 Graphs of Good Data 103

104 Day 7 Physics - Mr. Hill Agenda: Skywork Question: Making Sense of the Patterns with Friction Reading about Free Fall and Air Resistance Upcoming Next Week Short Answer Quiz on Forces Due Today Packet Page 7 & complete all of 2 Due Next Class Rd 6.6 & 6.7 Q s: 13,15,17,19,38,47 104

105 By the End of Class You Should Content Objective Have a working understanding of the role of Inquiry & into Science. Language Objective Be able to discuss a pattern with supporting evidence. 105

106 Board Meeting 106

107 Experimenting with the Force of Friction Friction (N) 25 static friction = * force pressed together 20 rolling friction = * force pressed together What is this? Force Pressed Together (N) 107

108 Experimenting with the Force of Friction stickiness factor 108

109 Experimenting with the Force of Friction stickiness factor stickiness factor 109

110 Experimenting with the Force of Friction Conclusion: Since the best-fit line of our data is linear for both static and rolling situations, we conclude that there is a linear relationship between the force of friction and the force two objects are pressed together. This can be represented mathematically static friction = * force pressed together rolling friction = * force pressed together So I predict with confidence, it will take N to pull a pile of 6 books stack on 10 rounds pens on a table, because. 110

111 Application Question Explain by referencing data, why we often put things on wheels or ball bearings when we want to easily or efficiently move things. As can be see in the graph of friction vs normal force, the can be reduced by a factor of by using wheels. That is, for a box weighing 20 N the friction without wheels would be N and be reduce to only N with wheels. 111

112 Test Prediction I get what Mr. Hill means when he says we take some measurements about how much friction there is when you change the surface or how hard to press the surfaces together, apply some mathematics to find a pattern, and than we can predict the amount of friction there will be in a new case involving the same surfaces. 112

113 Test Prediction Science works! We can find a pattern in nature and use it to accurately predict the future. Wild guess sometimes close, sometimes not. How do you know which of these it is? With careful investigation we can predict the future again and again with some level of confidence. 113

114 SQPRRS 6.6 & 6.7 Survey Question Predict Read Respond Summarize Due Tomorrow Rd 6.6 & 6.7 Q s: 13,15,17,19,38,47 114

115 Day 8 Physics - Mr. Hill Agenda: Skywork Question: Short Answer Quiz Free Fall, Air Resistance, & Terminal Velocity Seeing Forces in Motion Graphs Due Next Class Packet Page 8 Due Today Rd 6.6 & 6.7 Q s: 13,15,17,19,38,47 115

116 By the End of Class You Should Content Objective Have a working understanding of the role of Inquiry & into Science. Language Objective Be able to discuss a pattern with supporting evidence. 116

117 Short Answer Quiz 117

118 New Idea: Free Fall When a book, two books, and a crumpled sheet of paper are dropped at the same time rank the order in which they will hit the floor? Physics Physics Physics Why? 118

119 New Idea: Free Fall Video: What happens when remove the air? Physics Physics Physics Why? 119

120 Key Vocabulary Free Fall: Falling without significant air resistance. Terminal Velocity: The max speed an object can fall; since air resistance balances out the force of gravity causing the object to no longer speed up and instead it falls at a constant speed. 120

121 New Idea: Free Fall At terminal velocity: let s draw the forces on each object, label our guess at the time of fall it reaches terminal, and the speed it has when it does reach terminal velocity. Physics Physics Physics Why? 121

122 Review Data Tables Involving Acceleration Skydiving Time Acceleration (m/s2) Velocity (m/s) Distance (m)

123 The next slide involves skydiving with air resistance in a qualitative fashion. It should noted that it will look similar to constant acceleration at first then transition to looking like constant velocity when it reaches its terminal velocity. We will use this to introduce on forces show up in motion graphs. 123

124 Data Tables Involving Acceleration Skydiving with Air Resistance Time Acceleration (m/s2) Velocity (m/s) Distance (m)

125 Identifying Balanced & Unbalanced Forces in Graphs 125

126 Identifying Balanced & Unbalanced Forces in Graphs 126

127 Identifying Balanced & Unbalanced Forces in Graphs 127

128 Day 9 Physics - Mr. Hill Agenda: Skywork Question: Practice with Science Literacy Sample Passage next Slide Due Today Packet Page 8 Due Next Class Practice Science Literacy Reading 128

129 By the End of Class You Should Content Objective Become familiar with one framework of complex text. Language Objective Develop two new strategies for reading non-fiction texts. 129

130 Sample Passage 130

131 Sample Question 131

132 Answer 132

133 Dive In: Try Stopping Distance 5 minutes, then I will model my strategies. 133

134 Teacher Model with ACT Question As I carefully read this passage, I will talk out loud the ideas and strategies I use. 134

135 Teacher Guides ACT Question You work through a passage a notice what strategies you use and where you get stuck. First attempt to see if any strategy we discussed will help if not then ask me. 135

136 Teacher Steps-Aside ACT Question No short-cuts you must practice to get better but be intentional about your practice or it is wasted. Of course, I will help you but you are really seeing what you are capable of here. 136

137 Day 10 Physics - Mr. Hill Agenda: Applying Forces to a Bridge Review Force Unit Due Today Science Literacy Question Due Next Class Review Sheet Skywork Question: Think of an object that would fit for each of the following 3 scenarios: You lightly push and it doesn t move. You lightly push and it barely moves at a constant speed. You lightly push and it quickly accelerates away. 137

138 By the End of Class You Should Content Objective Have a working understanding of the role of Inquiry & into Science. Language Objective Be able to discuss a pattern with supporting evidence. 138

139 Finding Fnet and the resulting Acceleration 4N Mass is 2 kg 3N 139

140 Finding Fnet and the resulting Acceleration 8N 2kg 6N 140

141 Finding Fnet and the resulting Acceleration A 3D example Mass of block = 0.1 kg Support Force: 1 N up Weight: 1 N Down Push: 4 N Backwards Push: 3 N to the right 141

142 Force Situation that will come up in bridge project 10 kg Beam ( 20 kg) Wall Beam ( 20 kg) Wall Wall Wall 10 kg 10 kg Beam ( 20 kg) Beam ( 20 kg) Wall Wall Wall Wall 142

143 Force Situation that will come up in bridge project 143

144 Force Situation that will come up in bridge project 144

145 Force Situation that will come up in bridge project 145

146 Force Situation that will come up in bridge project a b c 50N d Ground, left Ground, Right 146

147 a b c 50N d Ground, left Ground, Right 1. Identify the forces acting inside beams A through D 2. Assuming that each beam has negligible mass (meaning that you do not have to think about it when calculating the weight) find the Weight that is being supported by the two support walls. 147

148 Review Force Unit 148

149 Acceleration vs Net Force Pattern: Linear so when F and when F F, a a F, a a 4 When Force is doubled, 2 acceleration is doubled

150 Acceleration vs Mass Pattern: Inverse so when m and when m m, a m, a a a When mass is doubled, acceleration will decrease by half

151 In an experiment, you use a spring scale to pull a 0.5 kg wood block. You observe the block does not move at first, even when you pull with 2.0 N of force. Immediately after pulling the slightest bit harder the block begins to accelerate. 151

152 152

153 Revisiting These Scenarios Need on poster paper to stay up Make your cartoons quantitative for the three scenarios with a cyclist: 1. Cyclist pedals kind of strong to go a constant 10 mph. 2. Cyclist pedals super strong to speed up to 25 mph. 3. Cyclist then has to pedal medium strong just to stay going a constant 25 mph. Visually: scene, Fpedal, Fair resistance, Fnet, Balance/Unbalanced + 1 sentence reasoning 153

154 Analyzing Surprising Situations with Forces Erin says Mr. Hill that stuff about interaction can t be right. When I drop a basketball it falls to the earth, the earth doesn t also fall towards the basketball. Think. Pair. Share. Write. Need on poster paper to stay up Mass of Basketball 0.6 kg Mass of Earth kg Force of interaction on each other W = mg = 6 N What impact will that have in changing each of their motions? What sort of acceleration is involve for each? What about of time is the change happening for? What will be the net movement of each in this time? 154

155 Newton s Three Laws 155

156 Review Sheet 156

157 End Below is optional material, not used this year 157

158 Do all Forces Feel the Same Pressure Bed of Nails Video 158

159 Day 11 Physics - Mr. Hill Agenda: Air Resistance Experiment Upcoming This Friday Test on Energy & Forces Due Today Packet 8,2,7 Due Tomorrow Packet 13 Skywork Question: If there is no air resistance all objects accelerate at 10 m/s2, but what happens if there is air resistance? Sketch a graph of Fnet vs time for a book and a coffee filter are dropped off the stadium 15 m high. 159

160 By the End of Class You Should Content Objective Have a working understanding of the role of Inquiry & into Science. Language Objective Be able to discuss a pattern with supporting evidence. 160

161 Experimenting with Air Resistance Wild Guess: How long will it take a coffee filter and a book to fall 4.5 meters? (Observation ) Research Question: How air resistance affects Fnet and velocity of objects? 161

162 Experimenting with Air Resistance Hypothesis: book v coffee filter t 1) Sketch in graph form (think about one set-up from previous slide then think doubling or halving the width) 162

163 Experimenting with Air Resistance Variables: 1. Identify the independent variables 2. Identify the dependent variables 3. Identify the controlled variables 163

164 Experimenting with Air Resistance Method: 1. Experimental set-up 2. How will you change the independent variables? 3. How will you control the controlled variables? 164

165 Experimenting with Air Resistance Value of controlled variables: Book = Object Height Fell(m) +/ kg Max Velocity (m/s) +/- 0.2 Trial 1 Trial 2 Trial 3 Filter = kg Average Max Velocity (m/s) +/- 0.2 Filter Book 165

166 Energy: How Height affects Speed X Y Height (m) +/ Time to Travel 2 m (s) +/- 0.4 Trial 1 Trial 2 Trial 3 Average Time (s) +/- 0.3 Velocity (m/s)