1. Chapter 4 Newton’s First Law of Motion: Inertia

2. Newton’s First Law - Inertia In Fancy Terms: Every object continues in a state of rest, or of motion in a straight line at constant speed, unless it is compelled to change that state by forces exerted upon it.

3. In Plain English: Objects in motion tend to stay in motion. Objects at rest tend to stay at rest.

6. Inertia Definition: the reluctance of any body to change its state of motion

7. Examples of Inertia Alphabet soup Removing tablecloth with dishes still on the table

8. So Why Do Things in Motion Stop?

9. Forces Definition: any push or pull

10. Friction Definition: the force that acts between materials that touch as they move past each other

11. - caused by irregularities in the surfaces of objects that are touching

12. - Even very smooth surfaces have microscopic irregularities that obstruct motion

13. MASS a measure of inertia measured in kilograms

14. MASS AND WEIGHT ARE NOT THE SAME THING!!!

15. Mass: quantity of matter in an object - independent of location

16. Weight: force of gravity on an object - depends on an object’s location

17. Mass and Weight are Proportional but NOT Equal a lot of mass = a lot of weight

18. SI unit of mass – kilogram SI unit of force - Newton

19. 1 kg = 9.8 Newtons (N) weight = mass x gravity w = mg

20. Net Force Definition: combination of all forces acting on an object

21. The net forces changes an object’s state of motion In the absence of a net force, objects do not change their state of motion

22. Normal Force Definition: the upward force that balances the weight of an object Also called support force

23. Other forces: Tension: At equilibrium – Tension = weight

24. Equilibrium Net force = zero

25. Chapter 5 Newton’s 2 nd Law

26. Remember: Acceleration = change in velocity time interval

27. What causes acceleration? Force

28. An objects acceleration is directly proportional to the net force Acceleration ~ net force

29. Mass resists acceleration Acceleration ~ 1/mass (inversely proportional)

30. Newton’s 2 nd Law: The acceleration produced by a net force on an object is directly proportional to the magnitude of the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object.

31. In other words : Acceleration = net force/mass a= F/m

32. Net Force Unit will always be Newtons. 1 N = kg*m/s 2

33. Free Body Diagram Definition: Diagram showing all the forces acting on an object.

35. Friction Reminder: Friction is the force that acts to oppose the motion between two materials moving past each other.

36. Types of Friction Static Rolling Fluid Sliding/Kinetic

37. Static Friction : resistance force that must be overcome to start an object in motion ex. pushing a desk when it is at rest

38. Rolling Friction: the resistance force between a surface and a rolling object ex. rolling a ball down a hill

39. Fluid Friction: the resistance force of a gas or liquid as an object passes through * fluids can be liquids or gases ex. air resistance

40. Kinetic/Sliding Friction: resistance force between two objects already in motion ex. sliding a book on the table

41. Force of sliding friction depends on the normal force and on the types of surfaces that are in contact with each other.

42. Magnitude of Force Force of sliding friction = (coefficient of sliding friction)*(normal force ) F f =  F N

43.  = coefficient of sliding friction If it’s high – object is not likely to slide easily If it’s low - found between very slippery surfaces

44. Applying Force Pressure = force per unit of area Measured in pascals (Pa) Pascal = N/m 2

45. Pressure = Force area of application P = F/A

46. Pressure is increased when surface area decreases! ex. bed of nails

49. Falling and Air Resistance Terminal velocity: speed at which acceleration of a falling object is zero because friction balances weight

51. Free Fall Explained F = F m m

52. Chapter 6 Newton’s 3 rd Law For every action there is an equal and opposite reaction

53. All actions occur in pairs

54. Action: Object A exerts force on Object B Reaction: Object B exerts force on Object A

55. Newton’s Law of Universal Gravitation Every object is attracts every other object with a force that for any two objects is directly proportional to the mass of each object.

56. In other words, the greater the masses, the greater the force of attraction between them

57. F = G m 1 m 2 d where G = 6.67 x 10 -11 Nm 2 /kg 2