1. Motion © David Hoult 2009

2. Displacement is distance moved in a specified direction © David Hoult 2009

3. Displacement is therefore a vector quantity Displacement is distance moved in a specified direction © David Hoult 2009

4. S I unit of displacement is the meter, m Displacement is therefore a vector quantity Displacement is distance moved in a specified direction © David Hoult 2009

5. “S I” - système international d'unités… the modern system based on the three fundamental units: Meter for distance © David Hoult 2009

6. “S I” - système international d'unités… the modern system based on the three fundamental units: Meter for distance Second for time © David Hoult 2009

7. “S I” - système international d'unités… the modern system based on the three fundamental units: Meter for distance Second for time Kilogram for mass © David Hoult 2009

8. All other units (for force, electric current, energy etc) are called derived units and are based on the three fundamental units of mass, distance and time. © David Hoult 2009

9. Speed is distance moved per unit time © David Hoult 2009

10. Speed is distance moved per unit time When stating a speed, no direction needs to be given because speed is a scalar quantity. © David Hoult 2009

11. Speed is distance moved per unit time When stating a speed, no direction needs to be given because speed is a scalar quantity. The units of speed are meters per second, ms -1 © David Hoult 2009

12. Velocity is distance moved per unit time in a specified direction (and sense) © David Hoult 2009

13. Velocity is distance moved per unit time in a specified direction (and sense) Velocity is therefore a vector quantity © David Hoult 2009

14. The units of velocity are meters per second, ms -1 Velocity is distance moved per unit time in a specified direction (and sense) Velocity is therefore a vector quantity © David Hoult 2009

15. Acceleration is the rate of change of velocity © David Hoult 2009

16. Acceleration is the rate of change of velocity Acceleration is therefore a vector quantity © David Hoult 2009

17. Acceleration is the rate of change of velocity Acceleration is therefore a vector quantity © David Hoult 2009

18. Acceleration is the rate of change of velocity Acceleration is therefore a vector quantity © David Hoult 2009

19. Acceleration is the rate of change of velocity Acceleration is therefore a vector quantity If the change took 20 seconds and was uniform then the speed (or velocity) changed by © David Hoult 2009

20. Acceleration is the rate of change of velocity Acceleration is therefore a vector quantity If the change took 20 seconds and was uniform then the speed (or velocity) changed by 5 meters per second each second © David Hoult 2009

21. The units of acceleration are meters per second per second, ms -2 © David Hoult 2009

22. Using Graphs to represent Motion © David Hoult 2009

25. Stationary body © David Hoult 2009

26. Stationary body © David Hoult 2009

28. Body moving with uniform velocity © David Hoult 2009

29. Body moving with uniform velocity © David Hoult 2009

30. Body moving with uniform velocity in the negative sense © David Hoult 2009

31. A B

32. Body B moving faster than body A A B © David Hoult 2009

33. The slope of a displacement / time graph gives the magnitude and sense of the velocity of the body © David Hoult 2009

34. Body accelerating © David Hoult 2009

35. If the acceleration is uniform the curve is a parabola © David Hoult 2009

36. Body accelerating © David Hoult 2009

37. Body accelerating in the negative sense © David Hoult 2009

40. Uniform velocity © David Hoult 2009

41. Uniform velocity in the negative sense © David Hoult 2009

43. Stationary body © David Hoult 2009

44. Body B moving faster than body A © David Hoult 2009

45. Body B moving faster than body A © David Hoult 2009

46. Body B moving faster than body A A B © David Hoult 2009

47. Body accelerating uniformly © David Hoult 2009

48. Body accelerating uniformly © David Hoult 2009

49. Body accelerating uniformly in the negative sense © David Hoult 2009

50. The slope of a velocity / time graph gives the magnitude and sense of the acceleration of the body © David Hoult 2009

51. Using a velocity / time graph to find displacement © David Hoult 2009

52. Using a velocity / time graph to find displacement © David Hoult 2009

53. Using a velocity / time graph to find displacement © David Hoult 2009

54. Using a velocity / time graph to find displacement In 8 seconds, the body moves 10 × 8 = 80 m © David Hoult 2009

55. Using a velocity / time graph to find displacement © David Hoult 2009

56. Using a velocity / time graph to find displacement The calculation of the displacement of the body is the same as calculating the area under the graph between 0 and 8 seconds © David Hoult 2009

57. The area under a velocity / time graph represents the displacement of the body © David Hoult 2009

58. Equations of Motion © David Hoult 2009

59. These equations are useful when bodies move with uniform acceleration. Symbols used in the equations: © David Hoult 2009

60. These equations are useful when bodies move with uniform acceleration. t represents time Symbols used in the equations: © David Hoult 2009

61. These equations are useful when bodies move with uniform acceleration. Symbols used in the equations: t represents time a represents acceleration © David Hoult 2009

62. These equations are useful when bodies move with uniform acceleration. Symbols used in the equations: t represents time a represents acceleration u represents “initial” velocity (or speed) © David Hoult 2009

63. u represents “initial” velocity (or speed) These equations are useful when bodies move with uniform acceleration. Symbols used in the equations: t represents time a represents acceleration v represents “final” velocity (or speed) © David Hoult 2009

64. These equations are useful when bodies move with uniform acceleration. t represents time Symbols used in the equations: a represents acceleration u represents “initial” velocity (or speed) v represents “final” velocity (or speed) s represents the displacement of the body from a reference point (usually the position of the body at t = 0) © David Hoult 2009

65. The average speed of a body can always be found using © David Hoult 2009

66. The average speed of a body can always be found using © David Hoult 2009

67. If the speed of a body changes from u to v and the acceleration is uniform © David Hoult 2009

68. If the speed of a body changes from u to v and the acceleration is uniform © David Hoult 2009

69. If the speed of a body changes from u to v and the acceleration is uniform © David Hoult 2009

70. If the speed of a body changes from u to v and the acceleration is uniform In this case the average speed is © David Hoult 2009

71. Therefore, to calculate the displacement of a body at time t, we might use © David Hoult 2009

72. Therefore, to calculate the displacement of a body at time t, we might use equation 1 © David Hoult 2009

73. From the definition of acceleration we have © David Hoult 2009

74. From the definition of acceleration we have This equation is often rearranged to allow us to find the speed (or velocity) of a body after a period of acceleration © David Hoult 2009

75. From the definition of acceleration we have This equation is often rearranged to allow us to find the speed (or velocity) of a body after a period of acceleration v = u + atequation 2 © David Hoult 2009

76. Combining equations 1 and 2 in order to eliminate v gives © David Hoult 2009

77. Combining equations 1 and 2 in order to eliminate v gives s = u t + ½ a t 2 equation 3 © David Hoult 2009

78. Combining equations 1 and 2 in order to eliminate v gives s = u t + ½ a t 2 equation 3 Combining equations 2 and 3 in order to eliminate t gives © David Hoult 2009

79. Combining equations 1 and 2 in order to eliminate v gives s = u t + ½ a t 2 equation 3 v 2 = u 2 + 2 a s equation 4 Combining equations 2 and 3 in order to eliminate t gives © David Hoult 2009

80. The Acceleration due to Gravity (g) (also called Acceleration of Free Fall) © David Hoult 2009

81. The Acceleration due to Gravity (g) (also called Acceleration of Free Fall) Experiments show that all bodies fall with the same acceleration © David Hoult 2009

82. The Acceleration due to Gravity (g) (also called Acceleration of Free Fall) Experiments show that all bodies fall with the same acceleration as long as air resistance is negligible. © David Hoult 2009

83. Experiments show that all bodies fall with the same acceleration as long as air resistance is negligible. g (in Paris) is about 9.8 ms -2 The Acceleration due to Gravity (g) (also called Acceleration of Free Fall) © David Hoult 2009

84. The value of g is not the same at all points on the Earth. © David Hoult 2009

85. The value of g is not the same at all points on the Earth. The value of g is affected by: © David Hoult 2009

86. The value of g is not the same at all points on the Earth. The value of g is affected by: i) altitude © David Hoult 2009

87. The value of g is not the same at all points on the Earth. The value of g is affected by: i) altitude © David Hoult 2009

88. The value of g is not the same at all points on the Earth. The value of g is affected by: i) altitude ii) latitude © David Hoult 2009

89. The value of g is not the same at all points on the Earth. The value of g is affected by: i) altitude ii) latitude; the Earth is not a perfect sphere © David Hoult 2009

90. The value of g is not the same at all points on the Earth. The value of g is affected by: i) altitude ii) latitude; the Earth is not a perfect sphere iii) the rotation of the Earth © David Hoult 2009

91. The value of g is not the same at all points on the Earth. The value of g is affected by: i) altitude ii) latitude; the Earth is not a perfect sphere iii) the rotation of the Earth The value of g is less than it would be if the earth did not rotate. © David Hoult 2009

92. The value of g is not the same at all points on the Earth. The value of g is affected by: i) altitude ii) latitude; the Earth is not a perfect sphere iii) the rotation of the Earth The value of g is less than it would be if the earth did not rotate. The value of g is affected most at places where the speed of circular motion is greatest, that is, on the equator © David Hoult 2009