Download Final Review Questions SOLUTIONS

Foundations of Technology – Semester Exam Review Questions [SOLUTIONS]
Mechanical Technology
1. a. Technology is the application of knowledge, tools, and skills to solve problems and extend human capabilities.
b. A technology system is a group of subsystems working together to solve problems and extend human
capabilities.
c. An artifact is something made by humans for a practical purpose.
2. 1) Defining a problem
2) Identifying criteria and specifying constraints
3) Researching and generating ideas
4) Brainstorming
5) Exploring possibilities
6) Selecting an approach
7) Developing a design proposal – purpose is to communicate final design and steps to construct it.
8) Making a model or prototype
9) Testing and evaluating the design, using specifications
10) Refining the design
11) Creating or making it
12) Communicating processes and results
2. Principle: a law of nature underlying the working of an artificial device
3. Mechanical technology: the technology of putting together mechanical parts to produce, control, and transmit
motion.
4. Machines: artifacts that transmit or change the application of power, force, or motion.
5. Machines can be simple or complex. Complex machines are made up of simple machines.
6. Core technologies are the “building blocks” of all technology.
7. a. Door latch: mechanical, structural, material
b. Fan: mechanical, electrical, structural, material
c. Crankshaft: mechanical, material, structural
d. Battery: structural, electrical, material
e. Thermostat: material, electronic, thermal
f. Cylinder: structural, material
g. Gas tank: structural, material
8. Simple machines work on the principle of the lever and the inclined plane.
9. Lever: lever, pulley, wheel and axle; Inclined plane: inclined plane, wedge, screw
10. First – fulcrum between force and load, Second – load between force and fulcrum, and Third – force between load
and fulcrum:
11.
12.
13.
14.
15.
16.
F x d = WORK
Wo / Wi = EFFICIENCY
A systematic application is an organized or established procedure, a set of steps.
“A” would be easier to push down.
The load of “B” will travel the greater distance.
A force multiplier is a machine that increases the force applied to the work at hand.
A distance multiplier is a machine that increases the distance the load moves.
“A” above is the force multiplier. “B” is the distance multiplier.
18. Mechanical Advantage (M.A.) is the number of times a mechanical device multiplies an applied force. The
equation for M.A. is
DF / DL
and
L / F.
19. A pulley is a mechanical device that is an adaptation of a wheel and axle. To find M.A. of a pulley, count the
total number of strands supporting the load.
20. A fixed pulley is a pulley attached or fixed to a strong structural member (system does not move). MA = 1.
21. A movable pulley is a pulley that is free to move since it is attached with a strand to a fixed structural member.
MA = 2.
22. A block and tackle is a system of three pulleys: 2 fixed and 1 movable. MA = 3.
FIXED
MOVABLE
BLOCK and TACKLE
Electrical Technology
23. Electrical Technology: the technology of producing, storing, controlling, transmitting and getting work from
electrical energy.
24. Ohm’s Law – the electric potential (voltage) applied to a circuit is equal to the product of the current flowing
through the circuit and the resistance impeding the flow of current through the circuit (V = I x R). Joule’s Law –
the power used by an electric circuit is equal to the product of the current flowing through the circuit and the
electric potential (voltage) applied to the circuit.
25. Amperes – measures current; Volts – measures electric potential (voltage); Ohms – measures resistance.
26. P = I2 x R
27. P = V2 / R
28. Electrons – Negative; Protons – Positive; Neutrons – Neutral
29. A circuit consists of (at least) a power source, a conductor, and a resistor.
30. Materials with “free electrons” are considered conductors (most metals); materials with “bound electrons” are
considered insulators (wood).
31. Electrons flow from the negative terminal of the power supply to the positive terminal of the power supply.
32. Voltage is the electric potential of an electric circuit; current is the rate of flow of electrons through a conductor;
resistance is the resistance to electron current (resisting an electric current generally creates heat).
33. Ohm’s Law – V = I x R; Joule’s Law – P = I x V
34. A schematic is a diagram that represents the components of a system without using actual pictures.
35.
DC:
AC:
Resistor:
Conductor:
Switch:
36.
37. A smaller-diameter wire has more resistance than a larger-diameter wire because there is a wider “path” for
electrons to flow in a larger-diameter wire. The wider the “path,” the lesser the resistance.
38. 1,000 W = 1 kW. 1,000 V = 1 kV.
39. Ohm – German mathematics teacher/professor, Ohm’s Law: V = I x R.
Joule – English physicist, Joule’s Law: P = I x V.
Faraday – English physicist and chemist; discovered that magnetic fields induce electric currents.
40. Conductors: Copper, Iron, Aluminum; Insulators: Glass, Wood, Cotton
41. The electromagnet on the electric motor was the bolt and the coil of wire wrapped around it.
42.
The graph on the left is an example of a DC power supply (1.5 volts) graphed over time. The graph looks this
way because a DC, or Direct Current, supply is constant over time; DC does not change unless the power source
is drained by use or other factors.
The graph on the right is an example of an AC power supply (120 volts) graphed over time. The graph fluctuates
between +120 volts and -120 volts, so its graph looks like that above. The reason AC (Alternating Current)
supplies actually alternate has to do with the generation of the electric current using a spinning electromagnet.
43. An electromagnet is a coil of wire and some metallic artifact (like an iron nail or bolt) that creates a variable
magnetic field that can be turned on and off.
44. 1) An electromagnet can be turned on and off; 2) the strength and direction of the magnetic poles of an
electromagnet can be controlled by altering the strength and direction of the electric current creating the
magnetic field.
45. The purpose of a switch is to provide a means to open and close (turn on and off) an electric circuit.
Fluid Technology
46. Fluid technology is the technology of using fluid, either gas (pneumatics) or liquid (hydraulic) to apply force or to
transport.
47. Boyle’s Law: the pressure and volume of an ideal gas are inversely proportional when temperature is constant.
48. Pressure and volume are inversely proportional. This means that P a 1/V and V a 1/P (pressure is proportional
to 1/V and volume is proportional to 1/P).
49. A pneumatic technology is a fluid technology using a gas. A hydraulic technology is a fluid technology using a
liquid.
50. Aerodynamics deals with the motion of air and other gaseous fluids; air and gases are fluids and are used in fluid
technology.
51. 1) All fluid technologies use a fluid, either gaseous or liquid; 2) All fluid technologies contain a pressure
difference that creates a net force.
Thermal Technology
52. 1) Thermal Technology – the technology of producing, storing, controlling, transmitting and getting work from
heat energy.
2) Thermodynamics - the science dealing with internal energy, heat, and work
3) Photon – a particle of light
4) Conduction – the transfer of heat through a substance by collision of molecules.
5) Convection – is the transfer of heat by movement of a fluid.
6) Radiation – the transfer of energy by electromagnetic waves.
53. Furnace, Hot water heater, Toaster, Insulation, Heat exchanger, Refrigerator, Hot air balloon, Fan, Engine
cooling system, Oven, Blow-dryer, Thermos, Heat shrink, Styrofoam, Radiator, Blanket, Winter jacket, Wool
socks
54. The more powerful radiation heat is in the form of infrared light, which we cannot see with our natural eyes.
Therefore, infrared photography allows us to “see” the heat given off by objects even if the material is not hot
enough for there to be a color change.
55. 1) Natural Convection: Fluid surrounding a heat source receives heat and rises (due to lower density)
Surrounding cooler fluid moves in to replace it. Cooler fluid is heated, rises, and cycle continues.
2) Forced Convection: Fans or other means are used to propel a fluid. An convection current is induced. Car
engine and A/C are examples
56. White, Blue, Yellow, Orange, Red
57. Solid, Fluid, No medium
58. Thermal energy flows from regions of high temperature to regions of lower temperature.
59. The driving force for heat transfer is a difference in temperature.
60. The more accurate way of saying an object is “cold” is saying that it lacks heat.
61. 1) Conduction: the transfer of heat through a substance (typically a solid) by collision of molecules.
2) Convection: the transfer of heat by movement of a fluid.
3) Radiation: the transfer of heat by electromagnet waves
Optical, Material, and Bio-Technology
62. Optical technology is the technology of producing light; using light for information collecting, storing, retrieving,
processing and communicating; and using light to do work. Examples: Lightbulb, Light-emitting diode, Lenses
to magnify or reduce, Laser speed detector, Laser compact disk, Fiber-optic telephone communication, Laser
cutting tools, Laser surgical instruments.
63. Controlling light: block it, bend it, reflect it. Creating light: heat, electrical reaction, chemical reaction.
64. White light is regular light from the sun or from a light bulb; it contains all the colors of the rainbow, but you
have to split it up to see this. You can split white light using a prism.
65. 1) Laser light is monochromatic. It contains one specific wavelength of light (monochromatic = one color).
2) Laser light is very directional. A laser light has a very tight beam and is very strong and concentrated.
3) Lasers can be focused on a very small spot and can shine for long distances without spreading out very much,
unlike a flashlight, which spreads out a lot.
4) The spot contains a lot of energy—so much energy that some lasers can cut through thick metal, and
smaller ones are used as scalpels.
5) Lasers can also send information through long threads of glass called optical fibers. A single laser can send
thousands of phone conversations through a fiber at the same time.
66. Biotechnology is the technology of using, adapting, and altering organisms and biological processes for a desired
outcome.
67. 1) Health care (medical), 2) Food processing and agriculture, 3) Non-food uses of crops and other products,
4) Environmental uses
68. Materials technology is the technology of producing, altering, and combining materials. .
69. Aluminum baseball bats, Vinyl siding on houses, Fiberglass auto-body parts, Plexiglas, Bonded polyurethane
vehicle structures, High strength steels in car frames, Advanced alloys in airplane engines, Polymer composites in
airplane wings, Chromium steel alloy bicycle frame
70. 3 categories of materials: Natural, Synthetic, Composite
71. The physical properties of a material are a basic reason for selecting the material.
72. 1) Metals: Normally combinations of "metallic elements", Usually have free electrons, Good conductors of heat
and electricity, Strong but malleable, Lustrous (shiny, reflective) look when polished
2) Ceramics: Generally compounds between metallic and nonmetallic elements (oxides, nitrides, and carbides)
3) Plastics: Organic compounds based upon carbon and hydrogen, They have very large molecular structures,
Low density and are not stable at high temperatures.
4) Semiconductors: Electrical properties intermediate between metallic conductors and ceramic insulators
5) Composites: More than one material type
Structural Technology
73. The technology of putting mechanical parts and materials together to create supports, containers, shelters,
connectors, and functional shapes.
74. Tension structures: spider web, climbing rope. Compression structures: chair legs, book shelves
75. Father of modern science, Father of modern physics, First modern engineer.
76. 1) Inertia, 2) F = ma, 3) Action/Reaction. Structural technology based mainly on #3.
77. The earth is pushing up at you with 150 lbs. (or whatever else your weight may be).
78. Type, size, shape, and placement of material determines its strength.
79. 1) Beams are horizontal structural members, 2) Posts are vertical structural members, 3) a truss is an assemblage
of beams forming a rigid framework.
80. The goal of structural members is to be as light as possible without being too flexible or unstable.
81. Tacoma Narrows bridge (1940), Challenger Space Shuttle (1986), Columbia Space Shuttle (2003), Chernobyl
Nuclear Reactor (1986), 2007 Missouri bridge collapse
82. Trial and Error.
83. Common Sense.
84. 1) Compression: a pushing force; 2) Tension: a pulling force; 3) Torsion: a twisting force; 4) Shear: a sliding force.
85. Deflection is bending that results from both tension and compression acting on a structural member at the same
time.