1. < BackNext >PreviewMain Chapter 13 Forces and Motion Preview Section 1 Gravity: A Force of AttractionGravity: A Force of Attraction Section 2 Gravity and MotionGravity and Motion Section 3 Newton's Laws of MotionNewton's Laws of Motion Concept Map

2. < BackNext >PreviewMain Quick Write Do you know of a place where gravity does not exist? If so, where? Why or why not?

3. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 What You Will Learn Gravity affects all matter. Gravity is a force. The law of universal gravitation explains how distance, mass, and gravitational force are related. Weight depends on gravity, but mass does not.

4. < BackNext >PreviewMain Multiple Meanings TermCommon MeaningScientific Meaning lawrule from governmentdescription that predicts what will happen if something specific happens vacuumelectric appliance that sucks up small things a place with no matter (objects)

5. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 The Effects of Gravity on Matter Gravity is a force of attraction between objects that is due to their masses.

6. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 The Effects of Gravity on Matter All matter has mass. Gravity is a result of mass. Therefore, all matter is affected by gravity.

7. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 The Effects of Gravity on Matter Gravity between the objects of the solar system holds the solar system together.

8. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 The Effects of Gravity on Matter Earth has a huge mass. Therefore, Earth has strong gravitational force.

9. < BackNext >PreviewMain Sir Isaac Newton a British scientist Discovered the law of universal gravitation in1665.

10. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 Law of Universal Gravitation (Newton)-General The same unbalanced force that affects the motion of small objects (apple) also affects the motion of larger objects (moon). This unbalanced force = gravity. universal = applies to all objects in the universe

11. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 Law of Universal Gravitation (Newton)-Mass All objects in the universe attract each other through gravitational force. mass of objects = gravity between objects

12. < BackNext >PreviewMain Activity: Mass Judgments

13. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 Law of Universal Gravitation (Newton)-Distance The force of gravity depends on the distance between two objects. distance = force of gravity

14. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 Law of Universal Gravitation (Newton)-Solar System The gravitational force of the sun affects the movement of all the planets. This force helps them stay in orbit around the sun. So, the force of gravity has an important role in maintaining the shape of the solar system.

15. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 Weight and Gravitational Force weight = the gravitational force on an object SI unit of force = newton (N). Weight can change with the location of the object in the universe. spring scale

16. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 Mass and Gravitational Force Mass = the amount of matter in an object kilograms (kg) or grams (g) Mass does not change when gravitational force changes. balance scale

17. < BackNext >PreviewMain Section 1 Gravity: A Force of Attraction Chapter 13 Gravity and Static Objects Gravity also acts on nonmoving, or static, objects.

18. < BackNext >PreviewMain Lab: Mass and Weight

19. < BackNext >PreviewMain End of Section 1

20. < BackNext >PreviewMain Gravity and Motion (Ch. 13, Sect. 2)

21. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 What You Will Learn acceleration due to gravity air resistance projectile motion: horizontal motion and vertical motion.

22. < BackNext >PreviewMain Why It Matters Gravity affects the motion of everything that you drop or throw.

23. < BackNext >PreviewMain BrainPop: Acceleration

24. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Gravity and Falling Objects Acceleration = change in velocity over time Review: velocity = change in speed and/or direction weight = gravitational force (unbalanced)

25. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Gravity and Falling Objects All objects fall to the ground at the same rate because the force of gravity is the same for all objects near Earth’s surface. Acceleration = 9.8 m/s 2

26. < BackNext >PreviewMain Gravity and Falling Objects: Show these forces, using vectors, on graph paper.

27. < BackNext >PreviewMain Calculating the Change in Velocity Formula: Δv = g x t Δv = change in velocity g = acceleration due to gravity (always 9.8 m/s) t = time object falls (seconds)  Change in Velocity: Δv = 9.8 m/s x total seconds

28. < BackNext >PreviewMain Change in Velocity: Math Practice formula: Δv = 9.8 m/s x total seconds Δv =

29. < BackNext >PreviewMain Video Clip: The Physics of Skydiving

30. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Air Resistance and Falling Objects Air resistance is the force that opposes the motion of objects through air. Air resistance slows the acceleration of falling objects.

31. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Air Resistance and Falling Objects The amount of air resistance acting on a falling object depends on the size, shape, and speed of the object.

32. < BackNext >PreviewMain Forces and Motion Chapter 13 Show these forces, using vectors, on graph paper:

33. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Air Resistance and Falling Objects An object falls at its terminal velocity when the upward force of air resistance equals the downward force of gravity.

34. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Air Resistance and Falling Objects An object is in free fall if gravity is the only force acting on it. It can only happen in a vacuum or outer space, where there’s no air.

35. < BackNext >PreviewMain Lab: Parachutes and Air Resistance

36. < BackNext >PreviewMain Projectile Motion and Gravity vertical motion: gravity accelerates at 9.8 m/s 2 (if air resistance is ignored).

37. < BackNext >PreviewMain Projectile Motion and Gravity horizontal motion: not affected by gravity

38. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Projectile Motion and Gravity horizontal movement + vertical movement = a curved path

39. < BackNext >PreviewMain Forces and Motion Chapter 13 Show these forces, using vectors, on graph paper:

40. < BackNext >PreviewMain Poster Project: Projectile Motion

41. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Orbiting and Gravity An object is orbiting when it is moving around another object in space.

42. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Orbiting and Gravity The two movements that come together to form an orbit are similar to the horizontal and vertical movements in projectile motion.

43. < BackNext >PreviewMain BrainPop: Space Flight

44. < BackNext >PreviewMain Forces and Motion Chapter 13 Show these forces, using vectors, on graph paper:

45. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Orbiting and Gravity The path of an orbiting object is not quite a circle. Instead, the path is an ellipse. Centripetal force is the unbalanced force that makes objects move in an elliptical path. Gravity provides the centripetal force that keeps objects in orbit.

46. < BackNext >PreviewMain Lab: Circling Marbles

47. < BackNext >PreviewMain Section 2 Gravity and Motion Chapter 13 Orbiting and Gravity Gravity helps maintain the shape of the solar system by keeping large objects such as the planets in their orbit around the sun. Gravity also affects the movement of very small objects in the solar system, such as the tiny particles that make up the rings of Saturn.

48. < BackNext >PreviewMain End of Section 2

49. < BackNext >PreviewMain Section 3 Newton's Laws of Motion Chapter 13 What You Will Learn Newton’s three laws of motion

50. < BackNext >PreviewMain Section 3 Newton's Laws of Motion Chapter 13 Newton’s First Law An object at rest will remain at rest unless acted upon by an unbalanced force. An object in motion will remain in motion at a constant speed and in a straight line unless acted upon by an unbalanced force.

51. < BackNext >PreviewMain Friction makes Newton’s first law difficult aka “law of inertia” mass is a measure of inertia. –s–small mass = less inertia –l–large mass = more inertia Newton’s First Law

52. < BackNext >PreviewMain Section 3 Newton's Laws of Motion Chapter 13 Newton’s Second Law of Motion Acceleration of an object depends on the mass and the amount of force. greater mass = greater the force needed greater force = increase in acceleration

53. < BackNext >PreviewMain Forces and Motion Chapter 13

54. < BackNext >PreviewMain Section 3 Newton's Laws of Motion Chapter 13 Newton’s Third Law of Motion All forces act in pairs. When a force is exerted, there is always an equal and opposite reaction force.

55. < BackNext >PreviewMain Section 3 Newton's Laws of Motion Chapter 13 Newton’s First Law PBS Teachers — Resources For The Classroom

56. < BackNext >PreviewMain End of Section 3