1. REV.
February 24, 2009
DRILL Get out U3D Test Review Homework and go over with a partner Tomorrow’s test will cover the following topics:
Mechanical Technology
Engineering Design Process
Simple Machines and Engineering Problems
Input-Output Mechanisms
Mechanical Advantage
Efficiency and Work

2. Engineering Design Process
U3d-L1
Engineering Design Process
Defining a problem
Researching and generating ideas
Brainstorming
Identifying criteria and specifying constraints
Exploring possibilities
Selecting an approach
Developing a design proposal
Making a model or prototype
Testing and evaluating the design, using specifications
Refining the design
Creating or making it
Communicating processes and results

3. Problem Solving: Sketch a diagram on the RIGHT SIDE
List the given info on the LEFT SIDE
Write equation/formula (rearrange if necessary)
Substitute and Solve
Check your answer, then CIRCLE/BOX ANSWER

5. F = ?
L = 45 lbs.

6. F = ?
L = 75 lbs.

7. F = ?
L = 150 lbs.

8. U3d-L1
F x d = W
Wo / Wi = Eff

9. U3d-L3
1. A hot air balloon carries 200 lbs cargo, 150 lbs human, and 200 lbs materials up a distance of 2,000 feet. How much work did the balloon do (keep all units)?
F x d = W
550 lbs x 2,000 ft =
W = 1,100,000 ft-lbs.
F x d = W
150 lbs x d = 30,000 ft-lbs.
150 lbs. 150 lbs.
d = 200 ft.
A physical therapy doctor told his 150-lb patient to do 30,000 ft-lbs of work each day to rehabilitate his leg. The patient decides to climb a hill to perform this work. How high does the patient need to climb in order to meet his goal?

10. Output = 320 miles Input = 32 gallons Efficiency = ?
U3d-L2
1. You have a dog that weighs 50 pounds. You carry her up the stairs a total vertical height of 9 feet. How much work did you do (keep all units)?
F x d = W
50 lbs x 9 ft =
W = 450 ft-lbs.
2004 Hummer H2
Output = 320 miles
Input = 32 gallons
Efficiency = ?
Toyota Prius
Output = 500 miles
Input = 10 gallons
Efficiency = ?

11. DRILL (continued) Output = 320 miles Input = 32 gallons Efficiency = ?
U3d-L2
DRILL (continued)
2004 Hummer H2
Output = 320 miles
Input = 32 gallons
Efficiency = ?
Toyota Prius
Output = 500 miles
Input = 10 gallons
Efficiency = ?
Wo / Wi = Eff
320 mls / 32 gal =
Eff = 10 mpg
Wo / Wi = Eff
500 mls / 10 gal =
Eff = 50 mpg

12. Identify which Core technology is represented by the examples below:
U3d-L4
Identify which Core technology is represented by the examples below:
Door latch e. Crankshaft
Thermostat f. Cylinder
Fan g. Battery
Light bulb h. Gas tank
Mechanical
Electronic
Mechanical/Thermal
Optical
Mechanical
Structural
Electrical

13. MECHANICAL TECHNOLOGY
U3d-L1
MECHANICAL TECHNOLOGY
The technology of putting together mechanical parts to produce, control, and transmit motion.
Example applications:
Gear systems in a car transmission,
Brakes on a bicycle,
Agitator in a washing machine,
Latch on a door.
Springs in vehicle shocks

14. U3d-L1
Input - Output
Machines are artifacts that transmit or change the application of power, force, or motion.
What is an artifact?
something created by humans usually for a practical purpose.
Machines can be simple or complex
Complex machines are comprised of….
Inputs go in
Outputs come out
Simple Machines

15. SIMPLE MACHINES 1. COMPONENTS: Levers Pivot Points Linkage Joints
U3d-L1
SIMPLE MACHINES 1.
COMPONENTS:
Levers
Pivot Points
Linkage Joints
INPUT

16. U3d-L1
CLASSWORK/HOMEWORK
INSTRUCTIONS: Transmit the given input motion to the desired output motion using only the allowed components.
Correctly copy the following onto the remaining 2” x 2” boxes in your notebook.
input
input 2. 3. 4.
input
input
input 5. 6.

17. PRINCIPLE OF THE LEVER LEVER Lever Wheel and Axle Pulley
U3d-L4
PRINCIPLE OF THE LEVER
LEVER
3 Categories of simple machines based on the principle of the LEVER:
Lever
Wheel and Axle
Pulley

18. PRINCIPLE OF THE LEVER 1st 2nd 3rd LEVER Lever Arm Fulcrum
U3d-L4
PRINCIPLE OF THE LEVER
LEVER
Lever Arm
Fulcrum
Applied Force
Load
3 different Classes of levers:
1st
2nd
3rd

19. PRINCIPLE OF THE LEVER LEVER Which is 1st class? 1st class:
U3d-L4
PRINCIPLE OF THE LEVER
LEVER
1st class:
The fulcrum is between the load and the effort force
Which is 1st class?

20. PRINCIPLE OF THE LEVER LEVER Which is 2nd class? 2nd class:
U3d-L4
PRINCIPLE OF THE LEVER
LEVER
2nd class:
The load is between the effort and the fulcrum
Which is 2nd class?

21. PRINCIPLE OF THE LEVER LEVER Which is 3rd class? 3rd class:
U3d-L2
PRINCIPLE OF THE LEVER
LEVER
3rd class:
The effort is placed between the load and the fulcrum
Which is 3rd class?

22. U3d-L4
LEVERS
Notice the direction of motion of the Force and Load for each of the 3 classes of lever.

23. A B Demonstrate it Sketch the pictures below and answer the questions:
U3d-L5
Sketch the pictures below and answer the questions:
Which lever would be easier to push down, A or B?
Which load will travel the greater distance, A or B? A B
Demonstrate it

24. SIMPLE MACHINES LEVER INCLINED PLANE
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SIMPLE MACHINES
Principle: a law of nature underlying the working of an artificial device
Simple machines work on 2 basic principles:
LEVER
INCLINED PLANE

25. LEVERS Which class is the lever below? Describe it. SECOND CLASS
U3d-L5
LEVERS
Which class is the lever below?
Describe it.
THIRD CLASS
SECOND CLASS
FIRST CLASS

26. PRINCIPLE OF THE LEVER WHEEL-and-AXLE A shaft attached to a disk
U3d-L5
PRINCIPLE OF THE LEVER
WHEEL-and-AXLE
A shaft attached to a disk

27. 2nd Class PRINCIPLE OF THE LEVER WHEEL-and-AXLE Which class of lever?
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PRINCIPLE OF THE LEVER
WHEEL-and-AXLE
Which class of lever?
2nd Class

28. 3rd Class PRINCIPLE OF THE LEVER WHEEL-and-AXLE Which class of lever?
U3d-L5
PRINCIPLE OF THE LEVER
WHEEL-and-AXLE
Which class of lever?
3rd Class

29. 1st Class PRINCIPLE OF THE LEVER PULLEYS
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PRINCIPLE OF THE LEVER
PULLEYS
Pulleys are grooved wheels attached to an axle.
Generally, what class lever do they act as?
1st Class

30. FORCE/DISTANCE MULTIPLIERS
U3d-L5
PRINCIPLE OF THE LEVER
FORCE/DISTANCE MULTIPLIERS
Simple Machines can be:
Force Multiplier: Increases the force applied to the work at hand
Distance Multiplier: Increases the distance the load moves

31. FORCE/DISTANCE MULTIPLIERS
U3d-L5
PRINCIPLE OF THE LEVER
FORCE/DISTANCE MULTIPLIERS
From the drill:
Which is the force multiplier?
In other words, which arrangement gives you greater strength A B

32. FORCE/DISTANCE MULTIPLIERS
U3d-L5
PRINCIPLE OF THE LEVER
FORCE/DISTANCE MULTIPLIERS
From the drill:
Which is the distance multiplier?
In other words, which arrangement gives you greater distance A B

33. F L DL DF DF DL L F FORCE MULTIPLIERS MECHANICAL ADVANTAGE M.A.= =
U3d-L8
FORCE MULTIPLIERS
MECHANICAL ADVANTAGE F L DL DF
MA is the number of times a mechanical device multiplies the Applied Force DF DL
M.A.= L F =
There are no units – it’s a ratio
What are the units for MA?
For All Lever Classes

34. You now have 2 equations:
U3d-L8
FORCE MULTIPLIERS
You now have 2 equations:
L x DL = F x DF
DF L
DL F =
Hint: They’re really the same equation rearranged

35. QUIZ REVIEW Machines are… What is an artifact?
U3d-L8
QUIZ REVIEW
Machines are…
artifacts that transmit or change the application of power, force, or motion.
What is an artifact?
something created by humans usually for a practical purpose.
Machines can be simple or complex
Complex machines are comprised of….
Simple Machines

36. Circumference = Pi * Wheel diameter
U3d-L8
PRINCIPLE OF THE LEVER
WHEEL AND AXLE
M.A. = Radius (D) to Force (F) = DF
Radius (D) to Load (L) DL
Rotary Motion
the circular motion which occurs when the wheel and axle are rotated about the centerline axis.
Linear Motion
the straight-line motion which occurs when a wheel rolls along a flat surface. The linear distance traveled when the wheel completes one revolution is equal to the circumference of the wheel.
Circumference = Pi * Wheel diameter

37. PRINCIPLE OF THE LEVER PULLEY
U3d-L8
PRINCIPLE OF THE LEVER
PULLEY
A pulley is an adaptation of a wheel and axle.
A single pulley simply reverses the direction of a force.
When two or more pulleys are connected together, they permit a heavy load to be lifted with less force.
The trade-off is that the end of the rope must move a greater distance than the load.

38. PRINCIPLE OF THE LEVER PULLEY MA = L / F
U3d-L8
PRINCIPLE OF THE LEVER
PULLEY
M.A. = Total number of strands supporting the load
MA = L / F

39. PRINCIPLE OF THE LEVER PULLEY 1 1 100
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PRINCIPLE OF THE LEVER
PULLEY
Fixed Pulley – when a pulley is attached or fixed to a strong member, which will not move.
How many strands are supporting the load?
What is the MA of a fixed pulley?
How many lbs of force are required to lift 100 lbs of load?
When a fixed pulley is used, the force needed to lift a weight does not change. 1 1
100

40. PRINCIPLE OF THE LEVER PULLEY
U3d-L8
PRINCIPLE OF THE LEVER
PULLEY
Movable Pulley – splits the work in half.
How many strands are supporting the load?
What is the MA of a movable pulley?
How many lbs of force are required to lift 100 lbs of load?
When a movable pulley is used, the force needed to lift a load is half that of the load. 2 2 50

41. PRINCIPLE OF THE LEVER PULLEY
U3d-L8
PRINCIPLE OF THE LEVER
PULLEY
Block and Tackle – a system of three pulleys
How many strands are supporting the load?
What is the MA of a movable pulley?
How many lbs of force are required to lift 120 lbs of load?
When a block and tackle is used, the force needed to lift a load is 1/3 that of the load. 3 3 40

42. PRINCIPLE OF THE INCLINED PLANE
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PRINCIPLE OF THE INCLINED PLANE
INCLINED PLANE
3 Categories of simple machines based on the principle of the INCLINED PLANE:
Inclined Plane
Wedge
Screw

43. PRINCIPLE OF THE INCLINED PLANE
U3d-L8
PRINCIPLE OF THE INCLINED PLANE
Inclined Plane – sloped surfaces used to make a job easier
Easier to go up a slope than a vertical surface
Wedge – used to split, separate, and grip
Wood chisel, firewood axe, doorstop
Screw – an inclined plane wrapped around a shaft
1/2-inch x 12 machine screw
½” diameter
12 threads per inch

44. PRINCIPLE OF THE INCLINED PLANE
U3d-L8
PRINCIPLE OF THE INCLINED PLANE
The inclined plane is the simplest machine of all the machines.
An inclined plane is a flat sloping surface along which an object can be pushed or pulled. An incline plane is used to move an object upward to a higher position.
M.A.= Distance = D
Height H H D L F

45. PRINCIPLE OF THE INCLINED PLANE
U3d-L8
PRINCIPLE OF THE INCLINED PLANE
During its use, an inclined plane remains stationary, while the wedge moves.
With an inclined plane the effort force is applied parallel to the slope of the incline.
With a wedge the effort force is applied to the vertical edge (height) incline.
FORCE
FORCE

46. PRINCIPLE OF THE INCLINED PLANE
U3d-L8
PRINCIPLE OF THE INCLINED PLANE
FORCE
FORCE D H
M.A.= D D H H