1. Wheel and Axle
Lever
Simple Machines
Pulley
Screw
Wedge
Inclined Plane

2. Would it require more work to take 100, 1kg books to the book room one at a time, or to take them in stacks of 20? Why???

3. Simple Machine
A machine is a device that does work. Machines do not decrease the amount of work done, but they do make work easier.

4. The magnitude of the force The direction of the force Or both
Why are they Useful?
They change:
The magnitude of the force
The direction of the force
Or both

5. A machine is a device that does work
A machine is a device that does work. Machines do not increase the amount of work done, but they do make work easier.

6. Machines make work easier by changing force or distance, or by changing the direction of the force.

7. There are two major categories of simple machines: the lever and the inclined plane.

8. Lever or Inclined Plane?
Wheel and Axle
Lever
Lever or Inclined Plane?
Pulley
Screw
Wedge
Inclined Plane

9. The wheel and axle, pulley, wedge, and screw are modifications of the two simple machines.

10. Example
Have you ever tried to unscrew screw from something with your bare hands?

11. What Did You Do?

12. You got the proper tool, such as a screw driver

13. So why is it so much easier to do with the screwdriver than your hand?

14. The screw driver is an examples of a wheel and axle,
The screw or bolt is the axle
The handle is the wheel. The tool makes the job easier by changing the amount of the force you exert.
Wheel
Axle

15. Simple machines make difficult tasks much easier

16. WORK MUST BE CONSERVED
Win = Wout
Fe x de = Fr x dr

17. EFFICIENCY
A measure of how much of the work put into a machine is changed into useful output work by the machine

18. All machines have efficiencies that are less than 100%. Why?

19. EFFICIENCY

20. If a machine outputs 50J of work and you input 100J of work, what is the efficiency of the machine?

21. A machine has an efficiency of 80% and has a work output of 50J
A machine has an efficiency of 80% and has a work output of 50J. What is the work input?

22. Force applied to the machine
EFFORT FORCE Fe
Force applied to the machine

23. Force applied by the machine to overcome resistance
RESISTANCE FORCE Fr
Force applied by the machine to overcome resistance

24. The number of times a machine multiplies the effort force
MECHANICAL ADVANTAGE
The number of times a machine multiplies the effort force

25. MECHANICAL ADVANTAGE

26. The force that you put into machine is 15N. The resistance force is 30N. What is the Mechanical Advantage?

27. The force effort is 10N. The resistance force is 8N
The force effort is 10N. The resistance force is 8N. Please calculate the Mechanical Advantage and explain what is interesting about this calculation.

28. The mechanical advantage is 20. The force effort is 5N
The mechanical advantage is 20. The force effort is 5N. What is the force resistance?

29. IDEAL MECHANICAL ADVANTAGE (for a lever)

30. IDEAL MECHANICAL ADVANTAGE (for a w&a)

31. Let's Take a Look at Them

32. Levers
Lever
Load
Fulcrum

33. Three classes of lever:
First Second Third
Crow bar Wheel Barrow Broom
Scissors Nutcracker Elbow
Can opener Bottle opener Baseball bat

34. SIMPLE MACHINES
LEVER
A lever is a simple machine.  It is a board or bar that rests on a turning point.  This turning point is called the fulcrum.  An object that a lever moves is called the load.  The closer the object is to the fulcrum, the easier it is to move.    

35. EXAMPLES OF LEVERS
A hammer is a lever when it is used to pull a nail out of a piece of wood.
Bottle openers
Crow bars

36. SIMPLE MACHINES
SCREW
  A screw is a simple machine that is made from another simple machine.  It is actually an inclined plane that winds around itself.  A screw has ridges and is not smooth like a nail.  Some screws are used to lower and raise things.  They are also used to hold objects together.  

37. EXAMPLES OF SCREWS Jar Lids Light Bulbs Stools Clamps Jacks Wrenches
Key Rings
Spiral Staircase

38. SIMPLE MACHINES
WEDGE
A wedge is a simple machine used to push two objects apart.  A wedge is made up of two inclined planes.  These planes meet and form a sharp edge.  This edge can split things apart.    

39. EXAMPLES OF WEDGES
Knives
Axes
Forks
Nails

40. SIMPLE MACHINES INCLINED PLANE
A simple machine that is a flat surface that is higher on one end.  You can use this machine to move an object to a lower or higher place.  Inclined planes make the work of moving things easier.  You would need less energy and force to move objects with an inclined plane. 

41. EXAMPLES OF INCLINED PLANES
Ramp
Slanted Road
Path up a Hill
Slide

42. SIMPLE MACHINES WHEEL AND AXLE
The wheel and axle is another simple machine.  The axle is a rod that goes through the wheel.  This lets the wheel turn.  It is easy to move things from place to place with wheels and axles. 

43. EXAMPLES OF WHEEL AND AXLE
Cars
Roller Skates
Wagons
Door Knobs
Gears in Watches, Clocks, and Bicycles

44. SIMPLE MACHINES PULLEY
This simple machine is made up of a wheel and a rope.  The rope fits on the groove of the wheel.  One part of the rope is attached to the load.  When you pull on one side of the pulley, the wheel turns and the load will move.  Pulleys let you move loads up, down, or sideways.  Pulleys are good for moving objects to hard to reach places.  It also makes the work of moving heavy loads a lot easier.    

45. EXAMPLES OF PULLEYS
Flag Poles
Clothes Lines
Sailboat
Blinds
Crane

46. The 6 Simple Machines Lever Inclined Plane Pulley Wheel and Axle Wedge
Screw

47. Examples
Teeter-totter or seesaw is an example of a class-one LEVER. The balance point, or fulcrum, is somewhere between the applied force and the load. This type of lever (class one) has three parts: the balance point or fulcrum, the effort arm where the force or work is applied, and the resistance arm where the object to be moved is placed.
The nail bar is also a lever, but it is a class-two lever (if you use the right end of the nail bar shown in the picture). A class-two lever is a lever with the effort and resistance forces on the same side of the fulcrum. To pry the nail with the right end of the bar shown, the fulcrum is the tip, the nail head applies a resistive force, and at the opposite end is the effort or work. Another example of a class-two lever is a wheel barrow.
The wheel chair ramp is an inclined plane. Although the distance up the ramp is greater than the distance straight up, less force is required.

48. More Examples
It can be difficult to understand the usefulness of a machine that increases the effort or force to move an object – that is, decreases advantage. If you keep in mind that machines allow us to optimize force and distance – increasing or decreasing one, while decreasing or increasing the other – this application makes more sense. Basically, the “trade off” for increased force is decreased distance. A fishing pole is a very good example. Explain. … another example is the handbrakes on bicycles.
Third Class Lever
In this class of levers, the force arm lies between the fulcrum and the load arm. Because of this arrangement, a relatively large force is required to move the load. This is offset by the fact that it is possible to produce movement of the load over a long distance with a relatively small movement of the force arm. Think of a fishing rod! Because of this relationship, we often employ this class of lever when we wish to produce large movements of a small load, or to transfer relatively low speed of the force arm to high speed of the load arm.
When a hockey stick or a baseball bat is swung, a third class lever is in effect. The elbow acts as a fulcrum in both cases and the hands provide the force (hence the lower arm becomes part of the lever). The load (i.e. the puck or the ball) is moved at the end of the stick or bat.
Example of third class levers are: a fishing pole, a pair of tweezers, an arm lifting a weight, a pair of calipers, a person using a broom, a hockey stick, a tennis racket, a spade, or a shovel.

49. ORGANIZER SIMPLE MACHINES WHAT IT IS HOW IT HELPS US WORK EXAMPLES
LEVER
A stiff bar that rests on a support called a fulcrum
Lifts or moves loads
Shovel, nutcracker, seesaw, crow-bar, elbow
INCLINED PLANE
A slanting surface connecting a lower level to a higher level
Things move up or down it
Slide, stairs, ramp, escalator
WHEEL AND AXLE
A wheel with a rod, called an axel, through its center: both parts move together
Doorknob, pencil sharpener, bike
Typically, machines are intended to reduce the amount of force required to move an object. But in the process, the distance is increased. A wheel chair ramp is easily visualized example of this relationship. While the amount of effort and strength is reduced (force) the actual distance is significantly increased. Therefore, the amount of actual work is the same.
While the typical applications of machines is to reduce effort or force, there are important applications of machines where this is no advantage – that is force is not reduced, or there is actually a decrease in advantage – that is, force is increased.
The best example of a machine that provides no advantage is a simple or single pulley. A single pulley only changes the direction of the effort force. A curtain pull is an example.

50. ORGANIZER SIMPLE MACHINES WHAT IT IS HOW IT HELPS US WORK EXAMPLES
PULLEY
A grooved wheel with a rope or cable around it
Moves things up, down, or across
Curtain rod, tow truck, mini-blind, flag pole, crane
WEDGE
A type of inclined plane with a sharp edge. The wedge moves, the inclined plane stays still.
Pushes things apart
Axe blade
SCREW
An inclined plane wrapped around a cylinder. Works with a lever.
Raises weights, presses or fastens objects
Screws, nuts
Typically, machines are intended to reduce the amount of force required to move an object. But in the process, the distance is increased. A wheel chair ramp is easily visualized example of this relationship. While the amount of effort and strength is reduced (force) the actual distance is significantly increased. Therefore, the amount of actual work is the same.
While the typical applications of machines is to reduce effort or force, there are important applications of machines where this is no advantage – that is force is not reduced, or there is actually a decrease in advantage – that is, force is increased.
The best example of a machine that provides no advantage is a simple or single pulley. A single pulley only changes the direction of the effort force. A curtain pull is an example.

51. Inclined Plane

52. Screw
A screw is an inclined plane wrapped around a post.

53. Wedge
Two inclined planes make a wedge.

54. Wheel and Axle
Wheel
Axle

55. Pulleys
Wheel
Rope

56. 3 classes of levers
Determined by position of load, fulcrum, and effort

57. 1st Class Lever
The claw on a hammer is a lever. We call this kind of lever a first-class lever.

58. 2nd Class Lever
A bottle opener is a second-class lever, which means the fulcrum is at the end of the lever and the load is in the middle.

59. 3rd Class Lever
A third-class lever has its fulcrum at one end and the load at the other end, with the work you do in the middle. It's how a fishing pole works. You lift just a short distance at the handle, but the end of the pole pops up several feet

60. A machine that is made up of one or more simple machines.
Complex Machine
A machine that is made up of one or more simple machines.