3. Simple machines

4. They decreases our applied force. Making work easier.
But do not reduce amount of work

5. 1. Lever

6. LEVER

7. 1st class lever

8. Scissors
Can opener

9. Crowbar

12. Mechanical advantage of simple machine

13. Find effort

14. Lever 120 cm long used to move 80 kg load
Lever 120 cm long used to move 80 kg load . From load to the fulcrum is 30 cm
Find effort

15. 2nd class lever

16. Wheelbarrow

17. Nutcracker

18. Bottleopener

19. Load 60 kg
Find force
Find mechanical advantage

20. In 2nd class lever load 150 N is holded by 25 N
Load distance from fulcrum 30 cm
Find effort distance and mechanical advantage

21. 3rd class lever

25. 2N is applied effort distance 5 cm.
Length of sugar tong is 10 cm. Find the mass of sugar

26. Find effort distance(2 cases…1 weight of rod is 0…2 weight of rod is 40 N)

27. Practice problems
Page 122 solve the following problems

28. 2. Pulley

29. Fixed Pulley

31. Movable pulley

35. Combination of pulleys
Combinations of pulleys

36. Load is moved by 10 m
Find how far was the rope pulled

37. If our force is 200 N. What is weight of an object??

38. 3. Wheel and axle

45. 4. Inclined plane

51. 5. Screw

53. Pitch

55. 42 turns 60 cm goes up
Find pitch

56. The length of a screw is 5,6 cm. Pitch is 0,8 mm
The length of a screw is 5,6 cm. Pitch is 0,8 mm. After how many turns will it penetrate totally to the wood

57. 6. Wheels and gears

58. N*R=n*r

59. Gear

60. Gear

61. 1st makes 10 revolutions

62. Practice problems Page 123 Answer the test questions 1-15