1. Motion Physical Science Chapter 11

2. Are You Moving ? You are sitting down, reading a book…. You are sitting down, reading a book…. Are you moving? Are you moving?

3. Motion Definition An object is in motion when its distance from another object is changing. An object is in motion when its distance from another object is changing.

4. Relative Motion Relative motion is movement in relation to a REFERENCE POINT. Relative motion is movement in relation to a REFERENCE POINT. This is called Frame of Reference. This is called Frame of Reference. Motion depends on the “Frame of Reference” Motion depends on the “Frame of Reference” Therefore an object is in motion if it changes position relative to a reference point. Therefore an object is in motion if it changes position relative to a reference point.

5. Frame of Reference Example Look at the figures. In fig.1, the car is to the right of the tree. In fig.2, after 2 seconds, the car is to the left of the tree. As the tree does not move, the car must have moved from one place to another. Therefore, here the tree is considered as the frame of reference

6. Distance vs. Displacement Distance is the length of a path between two points. Distance is the length of a path between two points. –SI unit?  Meters!! Displacement is the direction from the starting point and the length of a straight line from the starting point to the ending point. Displacement is the direction from the starting point and the length of a straight line from the starting point to the ending point. Sometimes it is the same as distance, but many times it is not.

7. Distance vs. Displacement Animation http://www.tutorvista.com/content/physic s/physics-i/motion/difference-distance- displacement.php http://www.tutorvista.com/content/physic s/physics-i/motion/difference-distance- displacement.php http://www.tutorvista.com/content/physic s/physics-i/motion/difference-distance- displacement.php http://www.tutorvista.com/content/physic s/physics-i/motion/difference-distance- displacement.php Another example! Another example! Another example! Another example! http://www.youtube.com/watch?v=Q9D0Y leyflc (Tutorial) http://www.youtube.com/watch?v=Q9D0Y leyflc (Tutorial) http://www.youtube.com/watch?v=Q9D0Y leyflc http://www.youtube.com/watch?v=Q9D0Y leyflc

8. Scalar Quantities Show magnitude only (magnitude can be size, length, or amount) Show magnitude only (magnitude can be size, length, or amount) –Examples: Speed, time, temperature, distance

9. Vector Quantities Show magnitude and direction Show magnitude and direction –Velocity, acceleration, force, displacement May be graphically represented May be graphically represented –Arrows Despicable Me – Vector video clip Despicable Me – Vector video clip Despicable Me – Vector video clip Despicable Me – Vector video clip

10. Vectors Vectors are a method used to visually show forces Vectors are a method used to visually show forces A vector is a quantity which has both magnitude (size) and direction. A vector is a quantity which has both magnitude (size) and direction. –The length of the arrow shows the magnitude of the vector. –The angle of the arrow shows the vector's direction. Just like numbers, we can add two or more vectors together and get a net force called the resultant Just like numbers, we can add two or more vectors together and get a net force called the resultant

11. Adding 2 or More Vectors Add vectors A and B to get the Resultant C Add vectors A and B to get the Resultant C A + B = C A + B = C Fig 1 - shows the magnitude & direction of the 2 vectors we are adding Fig 1 - shows the magnitude & direction of the 2 vectors we are adding Fig 2 – we move the beginning of vector B to the end of Vector A, making sure to keep the magnitude & direction exactly the same Fig 2 – we move the beginning of vector B to the end of Vector A, making sure to keep the magnitude & direction exactly the same Fig 3 – Connect the beginning of Vector A to the end of Vector B, this is your “Resultant” C. Fig 3 – Connect the beginning of Vector A to the end of Vector B, this is your “Resultant” C. Fig 1 Fig 2 Fig 3

12. Combining Displacements You can add vectors using “vector addition” You can add vectors using “vector addition” When two displacements have the same direction, you can add their magnitudes. When two displacements have the same direction, you can add their magnitudes. If two displacements are in opposite directions, the magnitudes subtract from each other. If two displacements are in opposite directions, the magnitudes subtract from each other.

13. Displacement along a Straight Line

19. Displacement that isn’t along a straight path Suppose a person moves 3 meters from A to B and 4 meters from B to C as shown in the figure. The total distance traveled by him is 7 meters. But is he actually 7 meters from his initial position? No, he is only 5 meters away from his initial position i.e., he is displaced only by 5 m, which is the shortest distance between his initial position and final position. Use Pythagorean’s Theorem! a 2 + b 2 = c 2

20. Distance vs. Displacement Problems http://www.tutorvista.com/content/physic s/physics-i/motion/distance-and- displacement-animation.php http://www.tutorvista.com/content/physic s/physics-i/motion/distance-and- displacement-animation.php http://www.tutorvista.com/content/physic s/physics-i/motion/distance-and- displacement-animation.php http://www.tutorvista.com/content/physic s/physics-i/motion/distance-and- displacement-animation.php

21. Distance vs. Displacement David walks 3 km north, then turns and walks 4 km east. Amy runs 2 miles south, then turns around and runs 3 miles north. Jermaine runs exactly 2 laps around a 400 meter track. Derrick crawls 4 feet then turns 90 degrees and crawls 6 feet. Ray runs 30 feet north, 30 feet west, and then 30 feet south. Jamison turns around 5 times. Cassidee walks 1 mile then turns 90 degrees and walks 2 miles. Taja walks two miles from her door to the park, then returns home to her door.

22. Distance vs. Displacement continued Sandy ran 3 blocks north, and then 2 blocks west. Neva swam 3 complete laps in a 50 meter pool. ( 1 lap is to the other side and back) John flies at a heading of 90 degrees for 20 km, turns to 270 degrees and flies for another 10 km before crashing into a flock of geese. Cameron flies at a heading of 180 degrees for 13 km, turns to 90 degrees and flies for another 30 km before crashing into the Alico building. Marissa flies at a heading of 270 degrees for 5 km, turns to 90 degrees and flies for another 10 km before crashing into Alex Alex flies at a heading of 0 degrees for 3 km, turns to 270 degrees and flies for another 4 km before crashing into Marissa Taylor flies at a heading of 90 degrees for 20 km, turns to 180 degrees and flies for another 25 km before crashing into a Bob Marley billboard.

23. Example problems What is the total distance of a person who over the course of a week ran a 5Km, 10Km, and biked a 150Km? Julia drove 2.56x10 5 m S to school today, and then drove 1.42x10 3 m N to Samantha’s house after school. What was her total displacement?

24. More Examples Chris drove 1300m W to Logan’s house then they drove 2500m S to meet Brittany and Whitney at Whitney’s house. From there they all drove 3800m E to watch the JV Football game, what was Chris’ total displacement?

25. Speed!!

26. Distance-Time Graphs The distance traveled by an object in a period of time often is expressed using a line graph. A line graph visually conveys information using sets of data points. 1.Copy the blank graph below on your paper. Complete the graph by plotting the given data points on the graph. Each set of data points represents (time, distance). Note that time is measured in seconds and distance is measured in meters. Connect the plotted points with a straight line. Data points: (0, 0), (2, 40), (4, 80), (6, 120), (8, 160), (10, 200) 2. Describe the motion shown on the graph 200

27. the object is traveling at a constant speed and/or that the object traveled 200 meters in 10 seconds

29. Speed Comparison of time and distance Comparison of time and distance –A scalar quantity (what does this mean?)  [magnitude only] –Distance units include: inches (in), feet (ft), miles (mi),meters (m), kilometers (km), centimeters (cm), light year, etc. –Time units include minutes (min), seconds (sec), hours (hr), years (yr), etc. –Speed can be any distance unit divided by any time unit!! –Mi/hr, ft/sec, km/min Distance traveled per unit time Distance traveled per unit time  S = d / t (speed = distance/time)  T = d / s  D = s x t What is the speed of a car that traveled 75 km in 1.5 hr? What is the speed of a car that traveled 75 km in 1.5 hr? S = D / T = 75km / 1.5 hr = 50 km/hr S = D / T = 75km / 1.5 hr = 50 km/hr

30. Speed Measured in m/s If you travel 2m in 1 sec, what is your speed? If you travel 15m in 12 sec, what is your speed? Car traveling at 80km/hr. What is this speed in m/s? 80 km x 1 hr x 1000m = 22.2 m/s hr 3600 sec 1 km

31. If the Algebra Stumps you!! V = d / t T = d / v D = v x t Divide here! Multiply here!

32. Speed Worksheet – p.1 Speed Worksheet – p.1

33. Velocity is speed with a direction Speed AND direction Speed AND direction –A vector quantity [magnitude & direction] Written like: 125 miles/hour east or 83 m/sec towards the house Written like: 125 miles/hour east or 83 m/sec towards the house What is the velocity of a jet that traveled 1623 mi North in 83 min? What is the velocity of a jet that traveled 1623 mi North in 83 min? – V = D / T –=1623 mi / 83 min –=19.5 mi/min North You can add velocities just like you did displacements, with vector diagrams You can add velocities just like you did displacements, with vector diagrams

34. Some Conversion formulas you may need: Write these in your notes!!!!! 1 mile = 1.609 km 1 km =.62 miles 1 mile = 5,280 feet 1 mile = 1,760 yards

35. Average speed - computed for the entire duration of a trip Instantaneous speed - measured at a particular instant, like when you check your speedometer

36. Average Speed Avg speed = total distance / total time V = d / t If a object moves at 104 km/hr for 12 hours, what distance has it traveled? If an object moves 640 km in 11 hours, what is its speed? If a car moves at an average speed of 60 mi/hr for 24 hours, what distance has it traveled? What is this distance in kilometers? (1 mile = 1.609 km)

37. Average Speed vs. Average Velocity Avg speed = total distance / total time V = D / t Avg velocity = total displacement / total time V = D / t

38. The slope of a line on a distance- time graph is speed

39. Average Speed (Average Velocity) What is the average speed after two minutes? What is the average speed between 2 and 4 minutes? What is the average speed for the entire trip? Answers on next slide!! Let’s see how you did!!

40. Answers for Average Speed or Average Velocity Average speed = total distance / total time Average speed = total distance / total time What is the average speed after 2 minutes? total distance is 75m, total time is 2 minutes. S = D/T S = 75m / 2min S= 37.5 m/min What is the average speed between 2 & 4 minutes? total distance: 110m – 75m = 35m total time: 4min – 2min = 2minutes total time S = D/T S = 35m / 2min S= 17.5 m/min

41. Speed Constant Speed Speed that does not change Speed that does not change –Instantaneous speed that does not change

42. Acceleration!!! Begins here!!

43. Speed-Time Graphs The speed an object travels in a period of time can be expressed on a graph. This type of graph can give useful information about the object’s motion. The speed-time graph of the object in Section 11.2 Interest Grabber is shown below. 1.Describe the speed of the object shown on the graph. 2.The slope of the line on a distance-time graph represents the change in distance (m) per the change in time (s). Thus, the slope of a distance-time graph gives speed (m/s). What information does the slope of a speed-time graph give you? 3.What is the slope of the line on the speed-time graph?

44. 1.Describe the speed of the object shown on the graph. The object is traveling at a constant speed of 20 m/s. 2.The slope of the line on a distance-time graph represents the change in distance (m) per the change in time (s). Thus, the slope of a distance-time graph gives speed (m/s). What information does the slope of a speed-time graph give you? The slope of a speed-time graph represents the acceleration of the object—its change in speed over the time. 3.What is the slope of the line on the speed-time graph? The slope of the line is 0.

45. Acceleration a change in speed, direction, or both. It is a vector We usually talk about positive acceleration, like a car speeding up or a rocket taking off. It can also be negative, like a car braking.

46. Acceleration A change in velocity A change in velocity –Speeding up  Positive acceleration –Slowing down  Negative acceleration  Deceleration –Changing direction

47. Acceleration The change in speed or velocity over time The change in speed or velocity over time –In the scientific community, the symbol for “change” is the triangle: –Change in velocity is found by subtracting the initial speed from the final speed V f - V i = V V f - V i = V The formula for acceleration is: A = V f - V i = V time time time time Therefore the units for acceleration are going to be a distance/time/time Example ft/min/sec v f v f is final velocity v i is initial velocity

48.   Notice if v i > v f you will have a negative acceleration!

49. Acceleration For an object to accelerate it must: For an object to accelerate it must: –Speed up (positive acceleration) –Slow down (negative acceleration a.k.a deceleration ) –Change direction of travel Each of these pictures depicts a type of acceleration: 1: the shuttle is speeding up every sec of the flight into orbit 2. the horse has come to a screeching halt (slowing down) 3. the baseball thrown to the batter is hit into the outfield (changed direction) 1 2 3

50. Change in direction Any time an object turns it has an acceleration Even though the speed may be constant, the direction is changing Constant acceleration is a steady change in velocity

51. Video Clip on Displacement, Velocity, and Acceleration http://www.youtube.com/watch?v=ITs6F1 _6qBM http://www.youtube.com/watch?v=ITs6F1 _6qBM http://www.youtube.com/watch?v=ITs6F1 _6qBM http://www.youtube.com/watch?v=ITs6F1 _6qBM

52. Acceleration due to gravity Known as free fall As something falls its velocity increases by 9.8 m/s every second Acceleration due to gravity = 9.8 m/s2 Falling objects video clip Myth busters Falling objects

53. Rolling ball incline video clip that shows how constant acceleration affects an object's motion. Rolling ball incline video clip that shows how constant acceleration affects an object's motion. Video clip If you are viewing this on my website, you can use this link: http://www.teachersdomain.org/resource/ lsps07.sci.phys.maf.ballincline/ http://www.teachersdomain.org/resource/ lsps07.sci.phys.maf.ballincline/ http://www.teachersdomain.org/resource/ lsps07.sci.phys.maf.ballincline/ http://www.teachersdomain.org/resource/ lsps07.sci.phys.maf.ballincline/

54. Review: Distance vs. Time graph The slope of a line on a distance-time graph is – –speed

55. Speed vs. Time graph Graph speed on y, time on x Slope equals – – acceleration.

56. The slope of the line represents – –The speed How does the slope during the first second compare to the slope during the fourth second? – –It is much greater during the fourth than the first What does this mean? – –An increasing speed means that the ball is accelerating.

57. What does it mean? What does a = 5 [m/sec 2 ] mean? What does a = 5 [m/sec 2 ] mean? If an object starts at rest, its velocity increases by 5 [m/sec] every second. If an object starts at rest, its velocity increases by 5 [m/sec] every second. Time (sec)AccelerationVelocity 05 m/sec 2 0 m/sec 15 m/sec 2 5 m/sec 25 m/sec 2 10 m/sec 35 m/sec 2 15 m/sec 45 m/sec 2 20 m/sec Therefore, an object accelerating at 5m/sec 2 will be travelling at 20 m/sec after 4 seconds.

58. Acceleration Problems: Calculate acceleration for the following data: Calculate acceleration for the following data: A = 60km/hr - 20 km/hr = 4 km/hr 10 sec sec A = 150m/sec - 50 m/sec = 20 m 5 sec sec 2 A = 1200km/hr - 25 km/hr = 587.5 km/hr 2 min min

59. Interactive On-Line Quiz Motion, Acceleration, Velocity Motion, Acceleration, Velocity Motion, Acceleration, Velocity Motion, Acceleration, Velocity –(http://www.quia.com/quiz/286600.html?AP_r and=777689445) (http://www.quia.com/quiz/286600.html?AP_r and=777689445(http://www.quia.com/quiz/286600.html?AP_r and=777689445

60. Motion Graphs Here is a power point presentation on Motion Graphs…this is also on my website. Here is a power point presentation on Motion Graphs…this is also on my website. You need to be able to interpret these!!

61. SASinschools Interactivity – Linear Motion #1198 – helps with reading speed and acceleration graphs!! Interactivity – Linear Motion #1198 – helps with reading speed and acceleration graphs!! Let’s do some of it together!!! Let’s do some of it together!!! http://www.sascurriculumpathways.com/P roductEntrance/Launch/launch.jsp?unit=1 198 http://www.sascurriculumpathways.com/P roductEntrance/Launch/launch.jsp?unit=1 198 http://www.sascurriculumpathways.com/P roductEntrance/Launch/launch.jsp?unit=1 198 http://www.sascurriculumpathways.com/P roductEntrance/Launch/launch.jsp?unit=1 198

62. Check this out??!! Virtual lab on velocity and acceleration in case you don’t understand!! Virtual lab on velocity and acceleration in case you don’t understand!! http://www.teachersdomain.org/resource/ phy03.sci.phys.mfw.accel/ http://www.teachersdomain.org/resource/ phy03.sci.phys.mfw.accel/ http://www.teachersdomain.org/resource/ phy03.sci.phys.mfw.accel/ http://www.teachersdomain.org/resource/ phy03.sci.phys.mfw.accel/

63. Inquiry Activity p.327 How Does a Ramp Affect a Rolling Marble? How Does a Ramp Affect a Rolling Marble?