Loading…

Flash Player 9 (or above) is needed to view presentations.
We have detected that you do not have it on your computer. To install it, go here.

Like this presentation? Why not share!

Like this? Share it with your network

Share

Describing Motion 2012

  • 6,597 views
Uploaded on

For our 2012 class.

For our 2012 class.

More in: Education , Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
No Downloads

Views

Total Views
6,597
On Slideshare
6,044
From Embeds
553
Number of Embeds
3

Actions

Shares
Downloads
73
Comments
1
Likes
1

Embeds 553

http://www.quia.com 496
http://turnerfenton.managebac.com 56
https://d303.blackboard.com 1

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Describing Motion Introduction to Kinematics 2012-13 Stephen Taylor & Paul Wagenaar Canadian Academy, KobeCanadian Academy inspires students toinquire, reflect and choose to compassionatelyimpact the world throughout their lives.
  • 2. How do you know that something is moving?Whee! By Todd Klassy, via the Physics Classroom Galleryhttp://www.flickr.com/photos/physicsclassroom/galleries/72157625424161192/
  • 3. How do you know that something is moving? Motion is change. Mechanics is the Science of Motion. Kinematics is the science of describing motion using graphs, words, diagrams and calculations. Our unit question: “How can we describe change?” Significant concept: Change can be communicated using descriptions, graphical representations and quantities.Whee! By Todd Klassy, via the Physics Classroom Galleryhttp://www.flickr.com/photos/physicsclassroom/galleries/72157625424161192/
  • 4. How can we describe change? • Distinguish between scalars and vectors. • Distinguish between distance and displacement. • Describe displacement of an object using components (coordinates), magnitude and direction and directed line segment vector diagrams. • Describe motion of an object in a given direction based on positive and negative displacement. • Calculate distance and displacement from a map. • Plot distance and displacement graphs from raw data or a strobe diagram • Distinguish between instantaneous and average speed/velocity. • Calculate average speed and velocity from a displacement-time graph or set of recorded data. • Analyze a displacement-time graph to show various types of motion (constant, resting, direction etc). • Analyze a velocity-time graph to describe changes in motion. • Draw and analyze vector diagrams to show velocity (magnitude and direction) • Convert velocity in km/h to m/s and vice-versa. • Calculate distance (displacement), speed (velocity) or time from a word equation giving other key information. • Define acceleration. • Calculate acceleration from a set of data. • Deduce a formula to determine instantaneous velocity from a given acceleration. • Explain why objects moving at constant speed can experience acceleration, but not those moving at constant velocity.Whee! By Todd Klassy, via the Physics Classroom Galleryhttp://www.flickr.com/photos/physicsclassroom/galleries/72157625424161192/
  • 5. Where are we going?http://www.slideshare.net/gurustip/qr-orienteering-rokko-islandComplete the QR Code orienteering courseto learn about describing motion using:• scalars and vectors• components• magnitude and direction• directed line segments
  • 6. Where are we going? North “West of North” “East of North” “North of West” “ North of East” West East “South of West” “ South of East” “ West of South” “ East of South” South
  • 7. “West of North” “East of North” North A B C“North of West” D “ North of East” G originWest East“South of West” “ South of East” F m.socrative.com/student/ E Room: N304 “ West of South” South “ East of South”
  • 8. Three ways of describing displacementComponents (coordinates or directional descriptors)- e.g. 3mE, 2mN of origin 2m 3m NorthMagnitude and Direction- described, e.g. 2.1m 35oN of WestVectors (directed line segments)- direction and magnitude are important N West E
  • 9. Scalars vs VectorsNon-directional quantities Quantities with direction Distance Displacement How far an object travels along a path Position of an object in reference to an origin or previous position Speed Velocity Rate of change of the position of an Rate of change of the position of an object object, e.g. 20m/s in a given direction, e.g. 20m/s East “per unit time” ΔdAverage speed or velocity v= Δt Change in distance or displacement Change in time More scalars: More vectors: Time Acceleration Energy Force Mass Electric field Volume
  • 10. Where are we going?Formative assessed task for Criterion E: Processing Data.As a group, present your completed course map,calculations and summary of what you learned on aposter. Comment on the reliability of the data.Individually design a new, 4-point course using allmethods of describing displacement. Location 4 may notbe back at the origin. Calculate total distance anddisplacement for the course.
  • 11. Where are we going?Individually design a new, 44-point course.Draw vector diagrams on themap. 3Two moves must be 2described using components.Two moves must bedescribed using magnitudeand direction.Calculate total distancealong vector diagrams. 1Calculate total displacementfrom the origin.This includes direction.Show all working.
  • 12. Unstoppable A runaway train with no brakes and a load of really dangerous chemicals is heading right for your town. How long have you got? What questions do you need to ask? http://www.youtube.com/watch?v=gWnfqSxp-DcTrain cartoon from: http://www.mytrucks.co.uk/how_to_draw_a_steam_train.htm http://en.wikipedia.org/wiki/CSX_8888_incident
  • 13. Unstoppable A runaway train with no brakes and a load of really dangerous chemicals is heading right for your town. How long have you got? d vxt http://www.youtube.com/watch?v=gWnfqSxp-Dc 210m in 10s 113.4km A BTrain cartoon from: http://www.mytrucks.co.uk/how_to_draw_a_steam_train.htm http://en.wikipedia.org/wiki/CSX_8888_incident
  • 14. How do I convert between m/s and km/h? 1 km h = m s = m s
  • 15. How do I convert between m/s and km/h? 1 km h 1000 m = 60 x 60 s = 1000 . 3600 m s 1 m/s = 3.6km/h To convert from m/s to km/h, multiply by 3.6. x 3.6 m/s km/h ÷ 3.6 To convert from km/s to m/s, divide by 3.6.
  • 16. Calculating Speed Practice 1. Three cyclists are in a 20km road race. A has an average speed of 30kmh-1, B is 25kmh-1 and C 22kmh-1. The race begins at 12:00. a. What time does rider A complete the course? d v t b. Where are riders B and C when A has finished? 0 10km 20km B A C 12:00Cyclist clipart from: http://www.freeclipartnow.com/d/36116-1/cycling-fast-icon.jpg
  • 17. Calculating Speed Practice 2. The speed limit is 40kmh-1. A car drives out of the car park and covers 10m in just 3s. Calculate: a. The speed of the car in kmh-1. d v t b. The car comes to a stretch of road which is 25m long. What is the minimum amount of time the car should to take to be under the speed limit?Car clipart from: http://www.freeclipartnow.com/transportation/cars/green-sports-car.jpg.html
  • 18. This is how far we’ve got.
  • 19. Splish Splash MrT and Mr Condon go swimming in the 25m RICL pool. Mr C is way faster than MrT. How long does it take MrC to lap MrT? How would you work it out? 25m in 20s 25m in 18s MrT MrCFree swimmer clipart from: http://www.clker.com/clipart-swimming1.html
  • 20. Are drivers speeding outside school? The speed limit is 40km/h. Convert this to m/s. 1 mile = 1.61kmhttp://www.youtube.com/watch?v=Qm8yyl9ROEMWhat are some of the OneWorld issues related tospeeding drivers?In what ways could sciencebe used to catch or preventspeeding drivers?
  • 21. Are drivers speeding outside school? Δd 20m v= Δt Aim: Test a quick method using cones and timers to determine whether a car is speeding outside the school or not. The speed limit is 40km/h. • Choose one of the methods on the following slides. • Record as many cars as you can in 15 minutes. • Show working of your calculations. • Consider uncertainties and errors in your results. Car Distance (m) Time (s) ± ____ Speed m/s ± ___ Speed km/h ± ±0.1m s ___ 1 20 2 20 3 20 4 20 5 20
  • 22. Are drivers speeding outside school? Δd 20m v= Δt Measure the time taken for cars to cover 20m. Record all cars passing school over a 15 minute period. Calculate each recording as m/s. Determine how many cars are breaking the speed limit of 40km/h. Show your working in the conversion from m/s to km/h. Calculate the minimum time a car must take to pass between the cones whilst remaining within the speed limit. Evaluate the method, noting limitations and possible improvements.
  • 23. Are drivers speeding outside school? Δd 20m v= Δt Measure the speed of all the cars that pass by the school in a 15-minute period. Determine how many cars are breaking the speed limit of 40km/h. Outline the conversion the app uses to get from metres and seconds to km/h. Calculate each recording as m/s. Calculate the minimum time a car must take to pass between the cones whilst remaining within the speed limit. Evaluate the method, noting limitations and possible improvements. Free app: http://itunes.apple.com/us/app/simple-radar- gun/id442734303?mt=8
  • 24. Are drivers speeding outside school? The local speed limit is 40kmh-1. Δd v= If we adopt the method of putting markers at set distances along each road, can you rearrange the Δt equation so that local people can determine whether or not a car is speeding – just by counting? t.v = d Sampled distance (you decide) This example: 50m d t=v = 50m = 50m = 50m = 4.5s 40kmh-1 40 x 1000 ( ) 11.1ms-1 3600
  • 25. Are drivers speeding outside school?Evaluate the method:• Are data reliable? (enough repeats, acceptable uncertainty/error)• Are data valid? (did we measure what we set out to measure?)• What are the limitations of the method, how might they have impacted the results and how could they be improved?
  • 26. Representing motion graphicallyDistinguish between distance anddisplacement.Sketch two curves for Michael Johnson:• Distance/time• Displacement/time http://www.youtube.com/watch?v=zbqy1Rpjgmw#t=2m18s 400 300 d (metres) 200 100 0 15 30 45 time (seconds)
  • 27. Walk This Way Using LoggerPro to generate distance/time graphs.Challenge 1: • Open the experiment “01b Graph Matching.cmbl” • Give everyone a chance to move themselves to follow the line as closely as possible. Make sure the motion sensor is aimed at the body the whole time. • Save some good examples and share them with the group. What does the line show? resting Fast constant motion Slow constant motion towards the sensor away from the sensor
  • 28. Walk This Way Using LoggerPro to generate distance/time graphs.Challenge 1: • Open the experiment “01b Graph Matching.cmbl” • Give everyone a chance to move themselves to follow the line as closely as possible. Make sure the motion sensor is aimed at the body the whole time. • Save some good examples and share them with the group. What does the line show? resting Slow constant motion towards the sensor Fast constant motion away from the sensor resting resting
  • 29. Walk This Way Using LoggerPro to generate distance/time graphs.Challenge 2: • Open the experiment “01a Graph Matching.cmbl” • Produce your own – differently-shaped - 10-second motion that includes all of the following characteristics: • Slow constant motion, fast constant motion and resting (constant zero motion) • Motion towards and away from the sensor • Acceleration • Changes in motionSave your graph and share itwith the group.Label the parts of the graph andadd it to your word doc forsubmission to Turnitin.
  • 30. Speed or Velocity?Speed is the rate of change of position of an object. Over time How fast is it moving? Speed is a scalar quantity. e.g. m/s (metres per second)Velocity is the rate of change of position of anobject – with direction. How fast is it moving in that direction? Velocity is a vector quantity. e.g. m/s East (metres per second to the East)
  • 31. Warm-up questions 1. Your average speed on a 64m journey is 80kmh-1. How long does it take? 2. A duck is on a pond. It starts 8m from the North edge and and swims for 10 seconds. It finishes 2m North of the edge. a. What was its velocity? b. Draw a vector diagram to show its displacement.
  • 32. Calculating Speed Δd At what speed did the object move away from the sensor? v= Δt Δd v= Δt
  • 33. Calculating Speed Δd At what speed did the object move away from the sensor? v= Δt Δd Δt v=
  • 34. Calculating Speed Δd At what speed did the object move away from the sensor? v= Δt Δd 2.5m – 1m = 1.5m 1.5m Δt 3s – 1s = 2s v= 2s
  • 35. Calculating Speed Δd At what speed did the object move away from the sensor? v= Δt Δd 2.5m – 1m = 1.5m 1.5m Δt 3s – 1s = 2s v= 2s = 0.75m/s
  • 36. Calculating Speed Δd At what speed did the object move away from the sensor? v= Δt Δd 2.5m – 1m = 1.5m 1.5m Δt 3s – 1s = 2s v= 2s = 0.75m/s (2d.p.)
  • 37. Calculating Speed Δd At what speed did the object move toward the sensor? v= Δt Δd v= Δt
  • 38. Calculating Speed Δd At what speed did the object move toward the sensor? v= Δt Δd Δt Δd v= Δt
  • 39. Calculating Speed Δd At what speed did the object move toward the sensor? v= Δt Remember: speed is a scalar, not a vector, so direction is not important Δd (don’t use negatives) 2.5m – 1.75m = 0.75m Δt 7.5s – 6s = 1.5s 0.75m v= 1.5s = 0.5m/s
  • 40. Instantaneous Speed Δd Is the speed of an object at any given moment in time. no line v= Δt X X X X X
  • 41. Instantaneous Speed Δd Is the speed of an object at any given moment in time. v= Δt X v = 0.00m/s X v = 0.5m/s X X v = 0.75m/s v = 0.00m/s X v = 0.00m/s
  • 42. Average Speed Δd Is the mean speed of an object over the whole journey. “mean” v= Δt Every movement adds to the total distance traveled Δd + Δd Δt = 10 seconds 1.5m + 0.75m v= 10s = 0.225m/s
  • 43. Calculating Velocity Δd At what velocity did the object move away from the sensor? v= Δt Δd v= Δt
  • 44. Calculating Velocity Δd At what velocity did the object move away from the sensor? v= Δt Δd Δt v=
  • 45. Calculating Velocity Δd At what velocity did the object move away from the sensor? v= Δt Δd 2.5m – 1m = 1.5m 1.5m Δt 3s – 1s = 2s v= 2s
  • 46. Calculating Velocity Δd At what velocity did the object move away from the sensor? v= Δt When the person moves away from the sensor, distance and Δd displacement are the same. 2.5m – 1m = 1.5m 1.5m Δt 3s – 1s = 2s v= 2s = 0.75m/s (away from sensor)
  • 47. Calculating Velocity Δd At what velocity did the object move away from the sensor? v= Δt When the person moves toward the sensor, displacement is lost. Δd 1.75m – 2.5m= -0.75m Δt v= 0.75m = -0.5ms -1 1.5s (toward sensor)
  • 48. Positives and Negatives in Velocity Velocity is direction-dependent. It can have positive and negative values. We can assign any one direction as being the positive. In the ball-throw examples, the data-logger has assigned movement away from the sensor (gaining displacement) as being the positive. Therefore movement towards the sensor is negative velocity. Identify which motions show positive, negative and zero velocity. North is positive. East is positive. South is positive. N
  • 49. Positives and Negatives in Velocity Velocity is direction-dependent. It can have positive and negative values. We can assign any one direction as being the positive. In the ball-throw examples, the data-logger has assigned movement away from the sensor (gaining displacement) as being the positive. Therefore movement towards the sensor is negative velocity. Identify which motions show positive, negative and zero velocity. North is positive. East is positive. South is positive. N +ve zero +ve -ve -ve
  • 50. Positives and Negatives in Velocity Velocity is direction-dependent. It can have positive and negative values. We can assign any one direction as being the positive. In the ball-throw examples, the data-logger has assigned movement away from the sensor (gaining displacement) as being the positive. Therefore movement towards the sensor is negative velocity. Identify which motions show positive, negative and zero velocity. North is positive. East is positive. South is positive. N +ve +ve +ve zero +ve -ve -ve -ve -ve +ve
  • 51. Positives and Negatives in Velocity Velocity is direction-dependent. It can have positive and negative values. We can assign any one direction as being the positive. In the ball-throw examples, the data-logger has assigned movement away from the sensor (gaining displacement) as being the positive. Therefore movement towards the sensor is negative velocity. Identify which motions show positive, negative and zero velocity. North is positive. East is positive. South is positive. N +ve +ve -ve zero +ve zero +ve -ve -ve -ve -ve +ve -ve +ve +ve
  • 52. Instantaneous Velocity Δd Is the velocity of an object at any given moment in time. v= Δt X X X X
  • 53. Instantaneous Velocity Δd Is the velocity of an object at any given moment in time. v= Δt X v = 0.00m/s X X v = 0.75m/s X v = 0.00m/s
  • 54. Instantaneous Velocity Δd Is the velocity of an object at any given moment in time. v= Δt X v = 0.00m/s X v = -0.5m/s X v = 0.75m/s Velocity is a vector. It is direction-specific. This point moving closer to the X origin can be negative. v = 0.00m/s
  • 55. Average Velocity Δd Is the mean velocity of an object over the whole journey. “mean” v= Δt v=
  • 56. Average Velocity Δd Is the mean velocity of an object over the whole journey. “mean” v= Δt v= 1.75m – 1.00m 10s = 0.075m/s (away from sensor) Δd Δt = 10 seconds
  • 57. Comparing Speed and Velocity Δd Mean speed is non-directional. ∆d = all distances Mean velocity is directional. ∆d = total displacement v= Δt v= 0.225m/s Mean speed v= 0.075m/s Mean velocity (away from sensor)
  • 58. Calculating Speed & Velocity ΔdCalculate the following in your write-ups. v= ΔtChallenge A: a) Your speed of movement away from the sensor b) Your average velocity over the 10-second runChallenge B: a) Your instantaneous velocity at any single point of constant motion b) b) Your average velocity over the 10-second runBall Challenge (coming up): a) Maximum velocity of the ball when falling b) Average velocity of the ball
  • 59. Walk This Way Using LoggerPro to generate distance/time graphs.Ball Challenge: • Open the experiment “02 Ball.cmbl” • Position the motion sensor on the floor or table, facing up. • Hold the volleyball about 3m above the sensor • Have someone ready to catch the ball before it hits the sensor. • Start the sensor, drop and catch the ball. Do this a few times. • Save and label the two graphs: distance/time and velocity/time. • Use these in your write-up to explain what is meant by velocity.
  • 60. Explain this! Distance from sensor (m) Velocity (ms-1)
  • 61. Explain this! Distance from sensor (m) Changing direction Slowing Speeding up Going upwards Falling Speeding up Resting Caught Velocity (ms-1) Let go Speeding up Slowing Resting Changing direction Speeding up (falling) Caught
  • 62. Walk This Way Submitting your workLab report • Assessed for Criterion E: Processing Data • Complete all the work in the class period to avoid homework. • Self-assess the rubric using a highlighter tool before submission. • Submit to Turnitin.com Pay attention to the task- specific clarifications to make sure you achieve a good grade
  • 63. Calculating values on a curve If we are calculating values of constant motion, life is easy. There is a straight line and we can draw a simple distance-time triangle to calculate speed or velocity. Distance from sensor (m) What about here? X Time (s)
  • 64. Calculating values on a curve If we are calculating values of constant motion, life is easy. There is a straight line and we can draw a simple distance-time triangle to calculate speed or velocity. Distance from sensor (m) What about here? X A triangle is not representative of the curve! Time (s)
  • 65. Calculating values on a curve If we are calculating values of constant motion, life is easy. There is a straight line and we can draw a simple distance-time triangle to calculate speed or velocity. Distance from sensor (m) If we draw a tangent to the curve at the point of interest we can use the gradient of the line to calculate the speed or velocity of the object – at that moment in time. X Time (s)
  • 66. Calculating values on a curve If we are calculating values of constant motion, life is easy. There is a straight line and we can draw a simple distance-time triangle to calculate speed or velocity. Distance from sensor (m) If we draw a tangent to the curve at the point of interest we can use the gradient of the line to calculate the speed or velocity of the object – at that moment in time. X Now the triangle fits the point. Time (s)
  • 67. Calculating values on a curve If we are calculating values of constant motion, life is easy. There is a straight line and we can draw a simple distance-time triangle to calculate speed or velocity. Distance from sensor (m) If we draw a tangent to the curve at the point of interest we can use the line to calculate the speed or velocity of the object – at that moment in time. X Now the triangle fits the point. Time (s) Δd v= = (0.6m – 0.25m) (0.4s) = 0.875m/s Δt
  • 68. This is a displacement-time graph for the One-Direction tour bus.• Did they really go in one direction? How do you know?• Calculate their velocity at 2s• Calculate their average velocity (over the whole journey)
  • 69. Speed and Velocity Δd v= A ball is thrown up in the air and caught. Determine: Δt a. The instantaneous velocity of the ball at points A and B b. The average velocity of the ball. 2 B A 1 0 0.5 1 Time (s)
  • 70. Velocity and Vectors Δd v= Velocity is a vector – it has direction. Δt We can use velocity vector diagrams to describe motion. The lengths of the arrows are magnitude – a longer arrow means + greater velocity and are to scale. The dots represent the object at consistent points in time. The direction of the arrow is important. Describe the motion in these velocity vector diagrams:origin Positive velocity, increasing velocity. + origin originorigin +
  • 71. Velocity and Vectors Δd v= Velocity is a vector – it has direction. Δt We can use velocity vector diagrams to describe motion. The lengths of the arrows are magnitude – a longer arrow means + greater velocity and are to scale. The dots represent the object at Positive velocity, decreasing velocity. Negative velocity, increasing velocity. consistent points in time. The direction of the arrow is important. Describe the motion in these velocity vector diagrams:origin Positive velocity, increasing velocity. + Negative velocity, increasing velocity. origin origin Object moves quickly away from origin, slows,origin Positive velocity, decreasing velocity. + turns and speeds up on return to origin.
  • 72. The birds are angry that the pigs destroyed theirVelocity and Vectors nests – but luckily they have spotted a new nesting site. However, short-winged and poorly adapted to flight, they need to use a slingshot to get there.Draw velocity vectors for each position of the angry bird to show its relative instantaneousvelocity. Use the first vector as a guide.The flight takes 2.3s. Calculate:• vertical displacement of the bird.• average velocity (up) of the bird.• average velocity (right) of the bird.• average overall velocity (include direction and magnitude) 1.6m 55cm 7.5 m
  • 73. Velocity and Vectors Draw velocity vectors for each position of the angry bird to show its relative instantaneous velocity. Use the first vector as a guide.
  • 74. Velocity and Vectors Draw velocity vectors for each position of the angry bird to show its relative instantaneous velocity. Use the first vector as a guide. Remember that velocity vectors represent velocity – not distance. So it doesn’t matter if there is an object in the way – the velocity is the same until the moment of impact.
  • 75. Velocity and Vectors Draw velocity vector diagrams for each of these karts. 10km/h 16km/h 8km/h 20km/h Use the known vector as the scale.
  • 76. Velocity and Vectors Draw velocity vector diagrams for each of these karts. 10km/h 16km/h 8km/h 20km/h Use the known vector as the scale.
  • 77. Velocity and Vectors A rugby ball is displaced according to the vector below, for 0.6 seconds. Determine the velocity of the ball. 2m 30o
  • 78. Velocity and Vectors A rugby ball is displaced according to the vector below, for 0.6 seconds. Determine the velocity of the ball. Δd 10 v= Δt = 0.6 = 16.7m/s (30o up and forwards) 2m 30o
  • 79. What do you feel when… … playing on a swing? (You know you’re not too cool for that) … taking off on an aeroplane? … driving at a constant 85km/h on the freeway? … experiencing turbulence on an aeroplane? … cruising at high altitude on an aeroplane? … slowing your bike to stop for a cat?
  • 80. Acceleration is the rate of change in velocity of an object origin 30 60 90 120 150 180 Which cars are experiencing acceleration? Find out here: http://www.physicsclassroom.com/mmedia/kinema/acceln.cfm Sketch distance – time graphs for each car (on the same axes) Distance What do the shapes of the lines tell us about the cars’ motion? Time
  • 81. Acceleration is the rate of change in velocity of an object Acceleration can be positive (‘speeding up’) or negative (‘slowing down’). An object at rest has zero velocity and therefore zero acceleration. An object at constant speed in one direction is not changing its velocity and therefore has zero acceleration. Velocity is a vector – the rate of change of displacement of an object. Displacement and velocity are direction-dependent. Therefore, a change in direction is also a change in acceleration. Δv a= Δt
  • 82. Acceleration Change in velocity Δv a= Δt = acceleration Initial velocity – final velocity (m/s) Time (s) Change in time m/s/s “Metres per second per second”
  • 83. Acceleration a = 3m/s/s Time (s) Velocity (m/s) Velocity (ms-1) 0 0 1 2 3 0 4 0 1 2 3 4formula Time (s)
  • 84. Acceleration a = 3m/s/s 12 Time (s) Velocity (m/s) 9 Velocity (m/s) 0 0 6 1 3 2 6 3 3 9 0 4 12 0 1 2 3 4formula Time (s)
  • 85. Acceleration a = 3m/s/s 12 Time (s) Velocity (m/s) 9 Velocity (m/s) 0 0 6 1 3 2 6 3 3 9 0 4 12 0 1 2 3 4 Time (s)formula v = 3t The velocity – time graph is linear as it is constant acceleration. This means it is increasing its velocity by the same amount each time. What would the distance – time graph look like?
  • 86. Acceleration a = 3m/s/s 12 A car accelerates at a constant rate of 3m/s/s. Time (s) Velocity Calculate its instantaneous velocity at 7.5s: 9 a. in m/s (m/s) Velocity (ms-1) 0 0 6 b. in km/h 1 3 2 6 3 Calculate the time taken to reach its 3 9 maximum velocity of 216km/h. 0 4 12 0 1 2 3 4formula v = 3t Time (s)
  • 87. Acceleration a = 3m/s 12Time (s) Velocity Displace- (m/s) ment (m) 30 9 0 Velocity (m/s) Displacement (m) 1 6 18 2 3 9 3 3 4 0 0 1 2 3 4 Time (s)formula Determine the velocity and displacement of the object each second. Plot the results on the graph. Compare the shapes of the two graphs.
  • 88. Acceleration a = 3m/s 12Time (s) Velocity Displace- (m/s) ment (m) 30 9 0 0 Velocity (m/s) Displacement (m) 1 3 6 18 2 6 3 9 3 9 3 4 12 0 0 1 2 3 4 Time (s)formula v = 3t The displacement – time graph is curved as it is constant acceleration – the rate of change of displacement increases. This means it is increasing its velocity by the same amount each time.
  • 89. Acceleration a = 3m/s/s 12Time (s) Velocity Displace- (m/s) ment (m) 30 9 0 0 0 Velocity (m/s) Displacement (m) 1 3 3 6 18 2 6 9 3 9 3 9 18 3 4 12 30 0 0 1 2 3 4 Time (s)formula v = 3t The displacement – time graph is curved as it is constant acceleration – the rate of change of displacement increases. This means it is increasing its velocity by the same amount each time.
  • 90. Acceleration a = -2ms-2 Time (s) Velocity (ms-1) Velocity (ms-1) 0 10 1 2 3 0 4 0 1 2 3 4 Time (s)formula
  • 91. Acceleration a = -2ms-2 Time (s) Velocity (ms-1) Velocity (ms-1) 0 10 1 8 2 6 3 4 0 4 2 0 1 2 3 4 Time (s)formula
  • 92. Accelerationa = 2kmh-1s-1 Time (s) Velocity (kmh-1) 0 10 1 2 3 0 4 0 1 2 3 4 Time (s)formula
  • 93. Accelerationa = 2kmh-1s-1 18 Time (s) Velocity (kmh-1) Velocity (kmh-1) 0 10 1 10 2 3 4 0 0 1 2 3 4formula Time (s)
  • 94. How is it possible for an object moving at constant speed toexperience acceleration, but not anobject moving at constant velocity?
  • 95. How is it possible for an object moving at constant speed to experience acceleration, but not an object moving at constant velocity? Image: Moon from northern hemisphere: http://en.wikipedia.org/wiki/Moon
  • 96. Who’s faster? Usain Bolt’s 100m world record: http://www.youtube.com/watch?v=3nbjhpcZ9_g Strobe diagram: each dot is the position of the runner after one second.Gump Bolt 0m 100mBolt vs Gump, from http://www.ew.com/ew/gallery/0,,20220853_20499114,00.html#20499196
  • 97. Graphing Motion Sketch a distance/ time graph for Gump and Bolt. Strobe diagram: each dot is the position of the runner after one second.Gump Bolt 0m 100mBolt vs Gump, from http://www.ew.com/ew/gallery/0,,20220853_20499114,00.html#20499196
  • 98. Plot a distance/ time graph for Gump and Bolt. Graphing Motion What other analysis can be carried out with these data? Discuss and do it! Strobe diagram: each dot is the position of the runner after one second.Gump Bolt 0m 100mBolt vs Gump, from http://www.ew.com/ew/gallery/0,,20220853_20499114,00.html#20499196
  • 99. Gump vs. Bolt Blog post: Describing Motion ReviewUse the Gump vs Bolt data to write a blog post.It will act as a review of the content of the unit (check the assessment statementson your review sheet), as well as an informative article for others.You can write it as: • A local reporter for the Greenbow, Alabama paper • A sports reporter writing about Bolt and the Olympics • A straight-up scientific explainer for HS students Look at the criteria and the assessment statements. As a small group, make Bolt vs Gump, from and share a list of task-specific clarifications. Check, draft, write, cite. http://www.ew.com/ew/gallery /0,,20220853_20499114,00.htmIt will be assessed for Criterion B: Communication in Science: l#20499196
  • 100. Bolt vs Blake: What do the data tell us?Infographic from: http://www.telegraph.co.uk/sport/olympics/olympic_infographics_and_data/9453618/London-2012-Olympics-battle-of-the-sprint-kings-Usain-Bolt-and-Yohan-Blake.html
  • 101. Unit Test: Describing MotionCriterion C: Knowledge & Understanding in Science
  • 102. Unit Test: Describing MotionCriterion C: Knowledge & Understanding in ScienceReflection on the back of the test:1. What have you learned during this ‘Motion’ unit that you didn’t know before?1. What have you learned about how you learn? If you’re done:1. Do you think your performance in the test is a • Rokko Liner Plans! good reflection of your learning? Why?1. Do you think the test was fair and allowed you to demonstrate what you had learned? How would you improve it?1. How will you build on this for next time?
  • 103. Rokko Liner Project
  • 104. Spare Slides
  • 105. B A C velocity D G time E F C B Ddistance A E time
  • 106. What are the coordinates of these objects? Coordinates can be used to describe an objects position or displacement. 2mE, 1mN origin
  • 107. Pick a mystery object.Describe the displacement to three other objects.Can another group deduce the objects? Example: From (mystery object) It is: • 1mE, 1mS to the ______________________ • 4mS to the ______________________ • 2mS, 4mE to the ______________________
  • 108. Pick a mystery object.Describe the displacement to three other objects.Can another group deduce the objects? Example: From (mystery object) It is: • 1mE, 1mS to the Big Squirrel • 4mS to the Enthusiastic Runner • 2mS, 4mE to the Tiny Cyclist
  • 109. Pick a mystery object.Describe the displacement to three other objects.Can another group deduce the objects? Example: From (Giant Acorn) It is: • 1mE, 1mS to the Big Squirrel • 4mS to the Enthusiastic Runner • 2mS, 4mE to the Tiny Cyclist The components (coordinates) of displacement tell us where the object has moved to overall, but they do not necessarily tell us the path it has taken.
  • 110. Which objects are:• 2.1m away from the origin at 14oN of East?• 5m away from the origin at 30oN of East?
  • 111. Which objects are:• 2.1m away from the origin at 14oN of East?• 5m away from the origin at 30oN of East?
  • 112. Magnitude and Direction tell us the displacement in terms ofthe most direct path. N E origin
  • 113. Magnitude and Direction can also be represented by directedline segments (vector diagrams). N E 1m The direction (angle relative to the orientation) and magnitude (length of the vector) are important.
  • 114. Which objects lie closest to these vectors?(directed line segments – hint, start at origin, length is important) A N E N B E N C E
  • 115. Which objects lie closest to these vectors?(directed line segments – hint, start at origin, length is important) A N E N B E N C E
  • 116. Describing displacement N Components (coordinates or directional descriptors) - e.g. 3mE, 2mN of origin Magnitude and Direction - described, e.g. 2.1m 14oN of origin Vectors (directed line segments) - direction and magnitude are important
  • 117. Describing displacement N Components (coordinates or directional descriptors) - e.g. 3mE, 2mN of origin Magnitude and Direction - described, e.g. 2.1m 14oN of origin Vectors (directed line segments) - direction and magnitude are important
  • 118. Ke$ha’s Day Out on Rokko Island N 1km1. Wake up in the morning (11am) feeling like P Diddy.2. Get a pedicure, 5kmE 2.5kmS of home.3. Then hit the clothes store, 30oNorth of East 5km away.4. Cruise along, top down, CD’s on. Along this vector (directed line segment) to club.5. Club closes 1am. Walk home.6. Arrive home 4am by most direct route. Wake up feeling like P Diddy $
  • 119. Ke$ha’s Day Out on Rokko Island N 1km1. Wake up in the morning (11am) feeling like P Diddy.2. Get a pedicure, 5kmE 2.5kmS of home.3. Then hit the clothes store, 30oNorth of East 5km away.4. Cruise along, top down, CD’s on. Along this vector (directed line segment) to club.5. Club closes 1am. Walk home.6. Arrive home 4am by most direct route. Club Wake up feeling like P Diddy $ Clothes Pedicure
  • 120. Ke$ha’s Day Out on Rokko Island N 1km1. Calculate: a. Total distance b. Total displacement c. Average speed d. Average velocity e. Average speed on the walk home. Club Wake up feeling like P Diddy $ Clothes2. Describe the displacement of the pedicurist from her house using: a. directed line segment Pedicure b. direction and magnitude
  • 121. Calculate velocity 0.5s before it hits the fabric. 0.2mSketch a velocity-time graph for this journey.
  • 122. Thrown up at 12m/sAccelerates down at 10m/s/sHits water at 4s.What is the velocity as it hits the water?What is the height of the bridge?
  • 123. THE ONE DIRECTION TOUR BUSImages adapted from http://www.fanpop.com/spots/one-direction/images/28558025/title & http://goo.gl/zJnql