# Forces and Motion: Understanding Newton's Laws

This chapter introduces the concept of forces and their role in changing the motion of objects. It explores Newton's three laws of motion and encourages students to reflect on their initial beliefs about forces and how they might change throughout the chapter.

## About Forces and Motion: Understanding Newton's Laws

PowerPoint presentation about 'Forces and Motion: Understanding Newton's Laws'. This presentation describes the topic on This chapter introduces the concept of forces and their role in changing the motion of objects. It explores Newton's three laws of motion and encourages students to reflect on their initial beliefs about forces and how they might change throughout the chapter.. The key topics included in this slideshow are forces, motion, Newton's laws, gravity, friction,. Download this presentation absolutely free.

## Presentation Transcript

1. Chapter Menu Chapter Introduction Lesson 1 Gravity and Friction Lesson 2 Newtons First Law Lesson 3 Newtons Second Law Lesson 4 Newtons Third Law Chapter Wrap-Up

2. Chapter Introduction How do forces change the motion of objects?

3. Chapter Introduction What do you think? Before you begin, decide if you agree or disagree with each of these statements. As you view this presentation, see if you change your mind about any of the statements.

4. Chapter Introduction 1. You pull on objects around you with the force of gravity. 2. Friction can act between two unmoving, touching surfaces. 3. Forces acting on an object cannot be added. Do you agree or disagree?

5. Chapter Introduction 4. A moving object will stop if no forces act on it. 5. When an objects speed increases, the object accelerates. 6. If an objects mass increases, its acceleration also increases if the net force acting on the object stays the same. Do you agree or disagree?

6. Chapter Introduction 7. If objects collide, the object with more mass applies more force. 8. Momentum is a measure of how hard it is to stop a moving object. Do you agree or disagree?

7. Lesson 1 Reading Guide - KC What are some contact forces and some noncontact forces? What is the law of universal gravitation? How does friction affect the motion of two objects sliding past each other? Gravity and Friction

8. Lesson 1 Reading Guide - Vocab force contact force noncontact force gravity Gravity and Friction mass weight friction

9. Lesson 1-1 A push or a pull is called a force . An object or a person can apply a force to another object or person. Types of Forces force from Latin fortis , means strong

10. Lesson 1-1 A contact force is a force that is applied when two objects touch. A force that one object can apply to another object without touching it is a noncontact force . Gravity and magnetic force are examples of noncontact forces. Types of Forces (cont.)

11. Lesson 1-1 What are some contact forces and some noncontact forces? Types of Forces (cont.)

12. Lesson 1-2 Gravity is an attractive force that exists between all objects that have mass. Objects fall to the ground because Earth exerts gravity on them. Mass is the amount of matter in an object. Mass is often measured in kilograms (kg). What is gravity?

13. Lesson 1-1 The SI unit for force is the newton (N). Arrows can be used to show both the strength and direction of force.

14. Lesson 1-2 Sir Isaac Newton developed the law of universal gravitation in the late 1600s. The law of universal gravitation states that all objects are attracted to each other by a gravitational force. What is gravity? (cont.)

15. Lesson 1-2 What is gravity? (cont.) What is the law of universal gravitation?

16. Lesson 1-2 The strength of force depends on the mass of each object and the distance between them. When the mass of one or both objects increases, the gravitational force between them also increases. What is gravity? (cont.)

17. Lesson 1-2 Weight is the gravitational force exerted on an object. Near Earths surface, an objects weight is the gravitational force exerted on the object by Earth. Because weight is a force, it is measured in newtons. What is gravity? (cont.)

18. Lesson 1-2 An objects weight is proportional to its mass. Near Earths surface, the weight of an object in newtons is about ten times its mass in kilograms. What is gravity? (cont.)

19. Lesson 1-3 Friction is a force that opposes the movement between two touching surfaces. There are several types of friction. static friction sliding friction fluid friction Friction

20. Lesson 1-3 Friction (cont.) static Science Use at rest or having no motion Common Use noise produced in a radio or television

21. Lesson 1-3 Static friction prevents surfaces from sliding past each other. Up to a limit, the strength of static friction changes to match the applied force. Sliding friction opposes the motion of surfaces sliding past each other. Friction (cont.)

22. Lesson 1-3 Fluid friction is friction between a surface and a fluidany material, such as water or air, that flows. Fluid friction between a surface and air is air resistance. Friction (cont.)

23. Lesson 1-3 What causes friction between surfaces? When the microscopic dips and bumps on one surface catch the dips and bumps on another surface, the microscopic roughness slows sliding. This is a source of friction. Friction (cont.)

24. Lesson 1-3 Friction (cont.) How does friction affect the motion of two objects sliding past each other?

25. Lesson 1-3 Lubricants decrease friction and with less friction, it is easier for surfaces to slide past each other. Reducing Friction

26. Lesson 1 - VS Forces can be either contact, such as a karate chop, or noncontact, such as gravity. Each type is described by its strength and direction.

27. Lesson 1 - VS Gravity is an attractive force that acts between any two objects that have mass. The attraction is stronger for objects with greater mass.

28. Lesson 1 - VS Friction can reduce the speed of objects sliding past each other. Air resistance is a type of fluid friction that slows the speed of a falling object.

29. Lesson 1 LR1 A. contact force B. gravity C. mass D. weight Which refers to gravitational force exerted on an object?

30. Lesson 1 LR2 A. gravitational force B. length C. mass D. noncontact force Which is proportional to an objects weight?

31. Lesson 1 LR3 A. net force B. lubricant C. gravity D. friction Which is a force that opposes the movement between two touching surfaces?

32. Lesson 1 - Now 1. You pull on objects around you with the force of gravity. 2. Friction can act between two unmoving, touching surfaces. Do you agree or disagree?

33. Lesson 2 Reading Guide - KC What is Newtons first law of motion? How is motion related to balanced and unbalanced forces? What effect does inertia have on the motion of an object? Newtons First Law

34. Lesson 2 Reading Guide - Vocab net force balanced forces unbalanced forces Newtons first law of motion inertia Newtons First Law

35. Lesson 2-1 The sum of all the forces acting on an object is the net force . The net force depends on the directions of the forces applied to an object. Because forces have direction, you have to specify a reference direction when you add forces. Identifying Forces

36. Lesson 2-1 A force moving in the reference direction is positive, and a force in the opposite direction is negative. When the forces applied to an object act in the same direction, the net force is the sum of the individual forces. Identifying Forces (cont.)

37. Lesson 2-1 When forces act in opposite direction on an object, the net force is still the sum of the forces. The net force is the sum of the positive and negative forces. Identifying Forces (cont.)

38. Lesson 2-1 Balanced forces are forces that combine and form a net force of zero. Forces that combine and form a net force that is not zero are unbalanced forces . Identifying Forces (cont.)

39. Lesson 2-2 According to Newtons first law of motion , if the net force on an object is zero, an object at rest will stay at rest, and a moving object will continue moving in a straight line with constant speed. As a result, balanced forces and unbalanced forces have different results when they act on an object. Newtons First Law of Motion

40. Lesson 2-2 Newtons First Law of Motion (cont.) What is Newtons first law of motion?

41. Lesson 2-2 Balanced forces acting on an object do not change the objects speed and direction. Newtons first law of motion only applies to balanced forces acting on an object. When unbalanced forces act on an object, the objects velocity changes. Newtons First Law of Motion (cont.)

42. Lesson 2-2 Newtons First Law of Motion (cont.) How is motion related to balanced and unbalanced forces?

43. Lesson 2-2 The tendency of an object to resist a change in its motion is called inertia . Newtons First Law of Motion (cont.) inertia from Latin iners , means without skill, inactive

44. Lesson 2-2 Newtons First Law of Motion (cont.) What effect does inertial have on the motion of an object?

45. Lesson 2-3 For an object to start moving, a force greater than static friction must be applied to it. To keep an object in motion, a force at least as strong as friction must be applied continuously. Objects stop moving because friction or another force acts on them. Why do objects stop moving?

46. Lesson 2 - VS Unbalanced forces cause an object to move. According to Newtons first law of motion, if the net force on an object is zero, the objects velocity does not change. Inertia is a property that resists a change in the motion of an object.

47. Lesson 2 LR1 A. balanced forces B. inertia C. net force D. unbalanced forces Which refers to forces that combine and form a net force that is not zero?

48. Lesson 2 LR2 A. friction B. inertia C. unbalanced forces D. velocity Which could cause an object to stop moving?

49. Lesson 2 LR3 A. zero B. one C. equal D. balanced When equal forces act on an object in opposite directions, what is the net force on the object?

50. Lesson 2 - Now 3. Forces acting on an object cannot be added. 4. A moving object will stop if no forces act on it. Do you agree or disagree?

51. Lesson 3 Reading Guide - KC What is Newtons second law of motion? How does centripetal force affect circular motion? Newtons Second Law

52. Lesson 3 Reading Guide - Vocab Newtons second law of motion circular motion centripetal force Newtons Second Law

53. Lesson 3-1 Forces change an objects motion by changing its speed, its direction, or both its speed and its direction. Velocity is speed in a certain direction. Only unbalanced forces change an objects velocity. How do forces change motion?

54. Lesson 3-1 When unbalanced forces act on an object at rest, the object begins moving in the direction of the net force. If the net force acting on a moving object is in the direction that the object is moving, the object will speed up. If the direction of the net force on an object is opposite to the direction the object moves, the object slows down. How do forces change motion? (cont.)

55. Lesson 3-1 When unbalanced forces act on a ball at rest, it moves in the direction of the net force.

56. Lesson 3-1 Unbalanced forces can change an objects velocity by changing the objects direction. Another name for a change in velocity over time is acceleration. Unbalanced forces make an object accelerate by changing its speed, its direction, or both. How do forces change motion? (cont.)

57. Lesson 3-2 According to Newtons second law of motion , the acceleration of an object is equal to the net force acting on the object divided by the objects mass. Newtons Second Law of Motion

58. Lesson 3-2

59. Lesson 3-2 The direction of acceleration is the same as the direction of the net force. Acceleration is expressed in meters per second squared (m/s 2 ), mass in kilograms (kg), and force in newtons (N). Newtons Second Law of Motion (cont.)

60. Lesson 3-3 Circular motion is any motion in which an object is moving along a curved path. In circular motion, a force that acts perpendicular to the direction of motion, toward the center of the curve, is centripetal force . Circular Motion

61. Lesson 3-3 Circular Motion (cont.) centripetal from Latin centripetus , means toward the center

62. Lesson 3-3 Circular Motion (cont.)

63. Lesson 3-3 Circular Motion (cont.) How does centripetal force affect circular motion?

64. Lesson 3-3 A satellite is an object that orbits a larger object. A satellite tends to move along a straight path because of inertia. Gravity is the centripetal force that keeps a satellite in orbit by changing its direction. Circular Motion (cont.)

65. Lesson 3 - VS Unbalanced forces cause an object to speed up, slow down, or change direction.

66. Lesson 3 - VS Newtons second law of motion relates an objects acceleration to its mass and the net force on the object.

67. Lesson 3 - VS Any motion in which an object is moving along a curved path is circular motion.

68. Lesson 3 LR1 A. acceleration B. centripetal force C. inertia D. velocity Which term refers to speed in a certain direction?

69. Lesson 3 LR2 A. acceleration B. centripetal C. circular D. unbalanced Which refers to motion along a curved path?

70. Lesson 3 LR3 A. inertia B. acceleration C. circulation motion D. centripetal force Which refers to a change in velocity over time?

71. Lesson 3 - Now 5. When an objects speed increases, the object accelerates. 6. If an objects mass increases, its acceleration also increases if the net force acting on the object stays the same. Do you agree or disagree?

72. Lesson 4 Reading Guide - KC What is Newtons third law of motion? Why dont the forces in a force pair cancel each other? What is the law of conservation of momentum? Newtons Third Law

73. Lesson 4 Reading Guide - Vocab Newtons third law of motion force pair momentum law of conservation of momentum Newtons Third Law

74. Lesson 4-1 When an object applies a force on another object, the second object applies a force of the same strength on the first object, but the force is in the opposite direction. Opposite Forces

75. Lesson 4-2 According to Newtons third law of motion , when one object applies a force on a second object, the second object applies an equal force in the opposite direction on the first object. Newtons Third Law of Motion What is Newtons third law of motion?

76. Lesson 4-2 A force pair is the forces two objects apply to each other. If the forces of a force pair always act in opposite directions and are always the same strength, they do not cancel each other out because each force acts on a different object. Newtons Third Law of Motion (cont.)

77. Lesson 4-2 Adding forces can only result in a net force of zero if the forces act on the same object. In a force pair, one force is called the action force and the other force is called the reaction force. Newtons Third Law of Motion (cont.)

78. Lesson 4-2 Newtons Third Law of Motion (cont.) Why dont the forces in a force pair cancel each other?

79. Lesson 4-3 When you push against an object, the force you apply is called the action force. The force applied by the object back against you is called the reaction force. According to Newtons third law of motion, every action force has a reaction force in the opposite direction. Using Newtons Third Law of Motion

80. Lesson 4-4 Momentum is a measure of how hard it is to stop a moving object. Momentum momentum from Latin momentum , means movement, impulse

81. Lesson 4-4 Momentum (cont.) Momentum is the product of an objects mass and velocity.

82. Lesson 4-4

83. Lesson 4-4 Momentum (cont.) An objects momentum is in the same direction as its velocity. According to Newtons first law, if the net force on an object is zero, neither its velocity nor its momentum change. Because momentum is the product of mass and velocity, the force on an object equals its change in momentum.

84. Lesson 4-5 According to the law of conservation of momentum , the total momentum of a group of objects stays the same unless outside forces such as friction act on the objects. Conservation of Momentum What is the law of conservation of momentum?

85. Lesson 4-5 When colliding objects bounce off each other, it is an elastic collision. If objects collide and stick together, the collision is inelastic. No matter the type of collision, the total momentum will be the same before and after the collision. Conservation of Momentum (cont.)

86. Lesson 4 - VS Newtons third law of motion describes the force pair between two objects. For every action force, there is a reaction force that is equal in strength but opposite in direction. In any collision, momentum is transferred from one object to another.

87. Lesson 4 LR1 A. Newtons third law of motion B. Newtons second law of motion C. Newtons first law of motion D. law of conservation of momentum Which law explains that every force has a reaction force in the opposite direction?

88. Lesson 4 LR2 A. velocity B. momentum C. inertia D. elastic collision Which is a measure of how hard it is to stop a moving object?

89. Lesson 4 LR3 A. velocity B. momentum C. force pair D. collision Which refers to the forces two objects apply to each other?

90. Lesson 4 - Now 7. If objects collide, the object with more mass applies more force. 8. Momentum is a measure of how hard it is to stop a moving object. Do you agree or disagree?

91. Chapter Review Menu Key Concept Summary Interactive Concept Map Chapter Review Standardized Test Practice

92. The BIG Idea An objects motion changes if a net force acts on the object.

93. Key Concepts 1 Friction is a contact force. Magnetism is a noncontact force. The law of universal gravitation states that all objects are attracted to each other by gravity. Friction can stop or slow down objects sliding past each other. Lesson 1: Gravity and Friction

94. Key Concepts 2 Lesson 2: Newtons First Law An objects motion can only be changed by unbalanced forces. According to Newtons first law of motion, the motion of an object is not changed by balanced forces acting on it. Inertia is the tendency of an object to resist a change in its motion.

95. Key Concepts 3 According to Newtons second law of motion, an objects acceleration is the net force on the object divided by its mass. In circular motion, a centripetal force pulls an object toward the center of the curve. Lesson 3: Newtons Second Law

96. Key Concepts 4 Newtons third law of motion states that when one object applies a force on another, the second object applies an equal force in the opposite direction on the first object. The forces of a force pair do not cancel because they act on different objects. According to the law of conservation of momentum, momentum is conserved during a collision unless an outside force acts on the colliding objects. Lesson 4: Newtons Third Law

97. Chapter Review MC1 A. weight B. mass C. inertia D. gravity Which term refers to the amount of matter in an object?

98. Chapter Review MC2 A. contact B. gravity C. mass D. noncontact Which refers to a force that is applied when two objects touch?

99. Chapter Review MC3 A. unbalanced B. terminal C. centripetal D. balanced Which term refers to forces that combine with a net force of zero?

100. Chapter Review MC4 A. velocity B. terminal velocity C. net force D. inertia The tendency of an object to resist a change in its motion is called what?

101. Chapter Review MC5 A. Newtons third law of motion B. Newtons second law of motion C. Newtons first law of motion D. law of conservation of momentum Which law states that the total momentum of a group of objects stays the same unless outside forces act on the objects?

102. Chapter Review STP1 A. weight B. noncontact C. inertia D. contact Which term refers to a force that one object can apply to another without touching?

103. Chapter Review STP2 A. contact B. gravitational C. noncontact D. static Which describes the magnetic force?

104. Chapter Review STP3 A. unbalanced B. proportional C. noncontact D. negative Which describes the net force of different forces acting in the same direction?

105. Chapter Review STP4 A. stops B. speeds up C. slows down D. changes direction If the net force acting on a moving object is in the direction that the object is moving, the object does what?

106. Chapter Review STP5 Which refers to the collision of objects that bounce off each other? A. elastic B. friction C. inelastic D. inertia

### Related

No related presentations.