1. FORCES AND MOTION

2. Targets(PBA) A. Define Motion B. Tell what describes a force. C. Identify different forces that act on objects. D. Determine the effect of net forces on an object. E. Distinguish balanced and unbalanced forces.

3. I. Newton’s 1 st Law of Inertia  Resistance to change in motion

5.  Depends on Mass

6. A. Motion  Change in position in relation to a reference point. (something not moving)

8. B. Contact Forces 1. Applied Force (Push / Pull)  Forces have……  Magnitude (strength) : measured in Newtons  Direction : R / L ; N, S, E, W

9. 2. Gravity  Force of attraction between objects that have mass.

10. 3. Normal Force  Acts in the opposite direction of gravity.  Newton’s 3 rd Law

11. 4. Friction (Kinetic : sliding)

12.  Drag : air / water resistance

15. C. Net Force (sum of forces) 1. UNBALANCED: Unequal strength. Causes a change in…… speed or direction 2. BALANCED : Opposite forces with________ strength Equal  zero net force  strait line motion at constant speed

18. Balanced or Unbalanced?

19. D. Free Body Diagrams

20. II. Non Contact Forces

21. Targets F. Explain the behavior of objects with mass, charge or magnetic properties in gravitational, electric or magnetic fields. G. Explain the effect of distance on field strength. H. Differentiate mass and weight. I. Describe the relationship between electric currents and magnetic fields and how generators utilize the relationship.

22. A. Gravitational Fields 1.

23. 2. Distance has a greater effect on gravitational force than mass.

24. 3. Mass and Weight  Mass is the amount of matter an object contains.  Weight is the amount of gravitational pull on an object.

26. B. Electrical Fields 1.

29. 2. Exists around objects with a charge.  Like charges repel. (+ +, - - )  Opposite charges attract. ( + - ) 3. Electric force weakens with increasing distance.

30. C. Magnetic Fields

32. 1. Exists around magnetic objects.  Like poles repel. (N – N, S – S)  Opposite poles attract. (N – S) 2. Magnetic force weakens with increasing distance

33. D. Electromagnetism  A magnet can generate electricity in conductors.  Electric currents can make magnetic fields.  The force is stronger if the current runs along a coiled wire (solenoid) wrapped around an iron bar. (electromagnet)

35. 1. Generators  Mechanical energy to electrical energy.  Spinning coils within a magnetic field causes the wires to carry a current.

36. Simple Generator

38. 2. Motors  Electrical energy to mechanical energy.  An electric current in a magnetic field will experience a force causing a coil to spin. (source of power)

39. Simple Motor

41. III. POTENTIAL ENERGY

42. A. Mechanical Energy 1. Potential:  Energy an object has because of its position.  Work done to change an objects natural position increases PE. 2. Kinetic:  Energy of an object in motion. (or waves, electrons, molecules)  Depends on mass and velocity.

43. B. Types of Potential Energy 1. Gravitational  Depends on mass, height and gravity.

44. Where is PE the greatest? KE?

46. 2. Elastic  Results from stretching or compressing an object.

49. 3. Chemical  Depends on the position and arrangement of atoms.  Changed by chemical reactions.  Chemical energy changed to other types of energy. (thermal, light, sound)

53. 4. Magnetic  Depends on the position of magnetic objects.  PE greatest when….. : like poles are forced together, lowest when they spring apart. : opposite poles are at the edge of attraction, lowest when they pull together.

55. 5. Electrical  Depends on the position and the magnitude of charges.  PE greatest when….. : distance between like charges decreases. : distance between opposite charges increases.