Technology (Grades 5–12)
Subtest 1 Sample Items
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Question 1
1. Which of the following fuels used in the large-scale generation of electricity releases the least amount of CO2 and other pollutants per unit of energy produced?
- biomass
- petroleum
- natural gas
- coal
Answer to question 1
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0001) Natural gas burns more efficiently than coal, oil, or biomass and hence releases fewer by-products of combustion. For the equivalent amount of heat released when burned, natural gas produces about 30% less carbon dioxide than petroleum, and about 45% less than coal. Unlike coal, biomass, and, to a lesser extent petroleum, natural gas also releases fewer particulates into the atmosphere because it contains fewer noncombustible components (e.g., ash) that remain behind after combustion.
Correct Response: C. (Objective 0001) Natural gas burns more efficiently than coal, oil, or biomass and hence releases fewer by-products of combustion. For the equivalent amount of heat released when burned, natural gas produces about 30 percent less carbon dioxide than petroleum, and about 45 percent less than coal. Unlike coal, biomass, and, to a lesser extent petroleum, natural gas also releases fewer particulates into the atmosphere because it contains fewer noncombustible components (e.g., ash) that remain behind after combustion.
Question 2
2. One of the earliest examples in the United States of constructing complex objects using standardized and interchangeable parts was the manufacture of:
- steam engines.
- guns.
- furniture.
- utomobiles.
Answer to question 2
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0001) Before the early 1800s most complex objects were made individually. Making each piece individually precluded using techniques of mass production in which an object passed down an assembly line where interchangeable, standardized parts were added to the object until it was complete. Eli Whitney is credited with producing the first set of guns with interchangeable parts in 1801, but it was not until 1816 that Simeon North created the first milling machine to produce interchangeable metal parts. North and John Hall were able to mass-produce guns using the milling machine to produce rough-forged parts that were then filed to gage by hand with filing jigs.
Correct Response: B. (Objective 0001) Before the early 1800s most complex objects were made individually. Making each piece individually precluded using techniques of mass production in which an object passed down an assembly line where interchangeable, standardized parts were added to the object until it was complete. Eli Whitney is credited with producing the first set of guns with interchangeable parts in 1801, but it was not until 1816 that Simeon North created the first milling machine to produce interchangeable metal parts. North and John Hall were able to mass-produce guns using the milling machine to produce rough-forged parts that were then filed to gage by hand with filing jigs.
Question 3
3. Which of the following historical events had the greatest influence on science and mathematics education along with related technological developments in the United States?
- the launching of Sputnik
- the Three Mile Island accident
- the Cuban Missile Crisis
- the ending of the Vietnam war
Answer to question 3
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0001) The success of the Russian satellite, Sputnik, pushed the United States to make science and technology education a national priority at a scale never seen before or since. The resulting accelerated pace of research led to the development of a large number of technologies, including technologies that created our modern era of digital electronics and the Internet.
Correct Response: A. (Objective 0001) The success of the Russian satellite, Sputnik, pushed the United States to make science and technology education a national priority at a scale never seen before or since. The resulting accelerated pace of research led to the development of a large number of technologies, including technologies that created our modern era of digital electronics and the Internet.
Question 4
4. Continued technological developments in the Internet and personal electronic devices have had an unprecedented effect on the ways people work, play, and interact. Which of the following issues poses the greatest challenge to the continued expansion of the resulting societal and economic benefits?
- technological limits
- security breaches
- health consequences
- market saturation
Answer to question 4
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0001) As people, businesses, and governments become increasingly interconnected in an ever more complex web of communication technologies, vulnerabilities and opportunities for cyber-crime and cyber-warfare proliferate exponentially. Greater numbers of vulnerabilities become exposed as interconnected digital technologies become more integrated into all levels of modern society, and the consequences of security breaches are much more serious. A significant amount of resources must be invested to secure and stabilize these systems.
Correct Response: B. (Objective 0001) As people, businesses, and governments become increasingly interconnected in an ever more complex web of communication technologies, vulnerabilities and opportunities for cyber-crime and cyber-warfare proliferate exponentially. Greater numbers of vulnerabilities become exposed as interconnected digital technologies become more integrated into all levels of modern society, and the consequences of security breaches are much more serious. A significant amount of resources must be invested to secure and stabilize these systems.
Question 5
5.
Specifications for a workpiece indicate that the piece is to have a length of 21 cm ± 3 mm and a width of 18 cm ± 3 mm. A workpiece having which of the following dimensions in centimeters would be acceptable?
Specifications for a workpiece indicate that the piece is to have a length of 21 centimeters plus or minus 3 millimeters and a width of 18 centimeters plus or minus 3 millimeters. A workpiece having which of the following dimensions in centimeters would be acceptable?
- 20.75 × 17.6520 point 75 by 17 point 65
- 20.65 × 17.7520 point 65 by 17 point 75
- 20.82 × 17.9520 point 82 by 17 point 95
- 21.40 × 18.2521 point 40 by 18 point 25
Answer to question 5
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0002) There are 10 mm in a cm, so the tolerance on this workpiece is .3 cm. In this case, tolerance means that anything within .3 cm above or below the specified measurement is acceptable. Thus, a length within a range of 20.7–21.3 cm and a width within a range of 17.7–18.3 cm would be acceptable. Only response C has measurements that lie within these ranges.
(Objective 0002) There are 10 millimeters in a centimeter, so the tolerance on this workpiece is point 3 centimeter. In this case, tolerance means that anything within point 3 centimeter above or below the specified measurement is acceptable. Thus, a length within a range of 20 point 7 to 21 point 3 centimeters and a width within a range of 17 point 7 to 18 point 3 centimeters would be acceptable. Only response C has measurements that lie within these ranges.
Question 6
6. Which of the following best explains why a design team usually builds a prototype during the design process of a product?
- to identify possible flaws in the design and evaluate how well the design works
- to define the key issues that the design team will face as they design the product
- to evaluate whether the product is needed and if it will be embraced by the market
- to narrow the ideas of the design team to a select few that may be most successful
Answer to question 6
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0002) At the end of the design process, a design team builds and tests a prototype. The purpose of the prototype is to provide a relatively cheap way to examine how well the design works. At this stage, flaws in the design can be identified and corrected, and the product evaluated before an expensive production process begins.
Correct Response: A. (Objective 0002) At the end of the design process, a design team builds and tests a prototype. The purpose of the prototype is to provide a relatively cheap way to examine how well the design works. At this stage, flaws in the design can be identified and corrected, and the product evaluated before an expensive production process begins.
Question 7
7. A greenhouse manager is growing tomato seedlings in a large bench filled with soil. Which of the following elements of the various technological systems used in this endeavor would be classified as a feedback mechanism?
- A timer turns on special growing lights at 7:00 p.m. and turns them off at 10:00 p.m. to extend relative day length.
- A soil probe measures moisture content and turns sprinklers on when the soil is too dry and off when it is moist.
- A fan set up at the end of the growing bed constantly circulates air through the plants to prevent fungus diseases.
- An automatic dispenser adds a small amount of foliar fertilizer to the water that is used in the overhead sprinklers.
Answer to question 7
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0002) Conditions in many systems must remain within certain specified parameters (e.g., temperature of the human body). Feedback mechanisms in a system monitor one or more conditions and detect when they do not meet the specified parameters. The feedback device then adds or takes away inputs into the system to return it to its normal state within the specified parameters. In this case, moisture content of the soil must remain within certain limits. When the probe detects that those limits have been exceeded (i.e., the soil is too dry), it will trigger an input of water that will correct the condition and return it to the steady state.
Correct Response: B. (Objective 0002) Conditions in many systems must remain within certain specified parameters (e.g., temperature of the human body). Feedback mechanisms in a system monitor one or more conditions and detect when they do not meet the specified parameters. The feedback device then adds or takes away inputs into the system to return it to its normal state within the specified parameters. In this case, moisture content of the soil must remain within certain limits. When the probe detects that those limits have been exceeded (i.e., the soil is too dry), it will trigger an input of water that will correct the condition and return it to the steady state.
Question 8
8. Use the diagram below to answer the question that follows.
Arrows run between the boxes in a clockwise direction in the following sequence: "Ask" to "Research" to "Imagine" to "Plan" to "Create" to "Test" to "Improve" and back to "Ask".
A teacher uses the diagram above to represent the engineering design process. In this representation of the design process, which of the following questions would be appropriate as a part of the "Ask" step?
- Does the design solve the problem?
- How could the design be made better?
- What are the design constraints?
- What materials should be used for the design?
Answer to question 8
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0002) While all of the general steps in the design process are essentially identical, there are variations in the language used and in the way the steps are broken down into sub-steps. In the design process cycle shown, the "Ask" step is the first step. This step relates to precisely defining the problem that needs to be solved. In this step, engineers ask about the design requirements, what needs the solution will address, who will use the final product or system, and what the design constraints (size, weight, cost, etc.) will be.
Correct Response: C. (Objective 0002) While all of the general steps in the design process are essentially identical, there are variations in the language used and in the way the steps are broken down into sub-steps. In the design process cycle shown, the "Ask" step is the first step. This step relates to precisely defining the problem that needs to be solved. In this step, engineers ask about the design requirements, what needs the solution will address, who will use the final product or system, and what the design constraints (size, weight, cost, etc.) will be.
Question 9
9. Which of the following is most likely to be a fixed cost for a company that manufactures plastic toys?
- the cost of packing material
- the cost of heating the building
- the cost of transporting products
- the unit cost of plastic
Answer to question 9
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. In manufacturing, a fixed cost is one that does not vary with the amount of product that is produced. Variable costs include all costs that vary with the amount of producing, packaging, and transporting the product. In this case, the cost of heating the building (response B) does not vary with the amount of product that is produced and is therefore a fixed cost.
Correct Response: B. In manufacturing, a fixed cost is one that does not vary with the amount of product that is produced. Variable costs include all costs that vary with the amount of producing, packaging, and transporting the product. In this case, the cost of heating the building (response B) does not vary with the amount of product that is produced and is therefore a fixed cost.
Question 10
10. The equilibrium price of a product is best defined as the:
- price at which the supply of the product is the same as demand for the product.
- average price for the product at all of the outlets in which the product is sold.
- price for the product that equals the variable and fixed costs of its manufacture.
- manufacturer's suggested retail price before retailers' mark-ups or sales promotions.
Answer to question 10
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0003) Two of the most important determinants of the price of a product are consumer demand for the product and the available supply of the product. Supply and demand can be plotted on a graph on which the x-axis represents the number of units available, and the y-axis is the price per unit. Rising prices will cause increases in production which will increase supply, but decrease demand. The reverse is true for falling prices. Thus, the curves for demand and supply slope in opposite directions. Where the two lines cross, supply is equal to demand and this is defined as the equilibrium price for the product.
Correct Response: A. . (Objective 0003) Two of the most important determinants of the price of a product are consumer demand for the product and the available supply of the product. Supply and demand can be plotted on a graph on which the x-axis represents the number of units available, and the y-axis is the price per unit. Rising prices will cause increases in production which will increase supply, but decrease demand. The reverse is true for falling prices. Thus, the curves for demand and supply slope in opposite directions. Where the two lines cross, supply is equal to demand and this is defined as the equilibrium price for the product.
Question 11
11. Two partners have run a small drafting business for several years. The business has been very successful and the partners decide to incorporate. The most likely reason why the partners decided to change the business ownership from a partnership to a corporation is to:
- lower the total personal and business tax burden on revenue from the business.
- raise capital for the expansion of the business by selling stock to investors.
- increase their individual roles in making decisions and planning for the business.
- take advantage of the looser federal laws and regulations that apply to corporations.
Answer to question 11
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0003) Sole proprietorships and partnerships have several advantages over corporations (e.g., less regulatory control, tighter ownership control over decision making, lower combined personal and business taxes). However, it is usually more difficult to raise money for expansion in a sole proprietorship or partnership, and capital is usually acquired in the form of loans that must be repaid with interest. Rather than taking on debt, the owners can raise capital by incorporating and selling stock, or shares, in the business to the public.
Correct Response: B. (Objective 0003) Sole proprietorships and partnerships have several advantages over corporations (e.g., less regulatory control, tighter ownership control over decision making, lower combined personal and business taxes). However, it is usually more difficult to raise money for expansion in a sole proprietorship or partnership, and capital is usually acquired in the form of loans that must be repaid with interest. Rather than taking on debt, the owners can raise capital by incorporating and selling stock, or shares, in the business to the public.
Question 12
12. Which of the following types of engineer would most likely take a leading role in building a suspension bridge across a river?
- mechanical engineer
- transportation engineer
- civil engineer
- manufacturing engineer
Answer to question 12
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0003) The field of engineering is very broad and encompasses a large variety of specialties (e.g., electrical engineering, aerospace engineering). Civil engineering is one of the oldest subdisciplines in engineering and is named to distinguish it from the equally old subdiscipline of military engineering. Civil engineers design and build nonmilitary structures in the natural environment, such as buildings, roads, bridges, and dams.
Correct Response: C. (Objective 0003) The field of engineering is very broad and encompasses a large variety of specialties (e.g., electrical engineering, aerospace engineering). Civil engineering is one of the oldest subdisciplines in engineering and is named to distinguish it from the equally old subdiscipline of military engineering. Civil engineers design and build nonmilitary structures in the natural environment, such as buildings, roads, bridges, and dams.
Question 13
13. Which of the following strategies would be most effective for a technology teacher to use for scaffolding students' reading comprehension of an academic text by promoting their awareness of the text's organizational structure?
- providing the students with explicit instruction in morphemic analysis skills using key words from the text
- showing the students how to use a semantic web to compare and classify content words used in the text
- encouraging the students to scan the text for unfamiliar vocabulary words before reading
- helping the students identify and analyze the transition words used to connect ideas in the text
Answer to question 13
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0004) Writers use various organizational text structures to help clarify the relationships between ideas in a text and to support the reader's recognition of the writer's argument or purpose. Common text structures for informational and expository texts include sequence or chronological order, comparison and contrast, and definition and example. A key element that helps signal most text structures is the use of transition words and phrases that are associated with a particular organizational structure. For example, a sequential or chronological text structure might use transitions such as first, meanwhile, and next, while a comparison/contrast text structure might use transitions such as although, on the other hand, and instead of.
Correct Response: D. (Objective 0004) Writers use various organizational text structures to help clarify the relationships between ideas in a text and to support the reader's recognition of the writer's argument or purpose. Common text structures for informational and expository texts include sequence or chronological order, comparison and contrast, and definition and example. A key element that helps signal most text structures is the use of transition words and phrases that are associated with a particular organizational structure. For example, a sequential or chronological text structure might use transitions such as start italics first, meanwhile end italics, and start italics next end italics, while a comparison/contrast text structure might use transitions such as start italics although, on the other hand end italics, and start italics instead of end italics.
Question 14
14. A student in a technology class is experiencing difficulty comprehending the text, even though the student demonstrates good understanding of discipline-specific concepts and vocabulary during class discussions. The technology teacher responds by asking the student to read aloud a representative section of text during a brief one-on-one conference. During the read-aloud, the teacher notes on a copy of the text any words the student omits or misreads. The teacher's action best demonstrates awareness of which of the following concepts related to content-area reading development?
- Adequate print processing skills such as decoding and fluency are prerequisite for supporting reading comprehension.
- Activating or building background knowledge related to a text's topic can support reading comprehension of the target text.
- Knowledge of various transition words that signal a text's organizational structure can support reading comprehension.
- Orthographic and morphological knowledge contribute to vocabulary knowledge, which in turn supports reading comprehension.
Answer to question 14
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0004) In this scenario, the student is experiencing comprehension difficulties with the text, even though the student has background knowledge related to the subject matter and demonstrates command of discipline-specific vocabulary; thus, some other factor must be affecting the student's reading comprehension. The teacher responds by listening to the student's oral reading of a selected section of the class text in order to note any miscues. Informal oral reading measures such as this can provide a teacher with important insight into a student's foundational reading skills (e.g., decoding ability, reading fluency), which are prerequisite for reading comprehension.
Correct Response: A. (Objective 0004) In this scenario, the student is experiencing comprehension difficulties with the text, even though the student has background knowledge related to the subject matter and demonstrates command of discipline-specific vocabulary; thus, some other factor must be affecting the student's reading comprehension. The teacher responds by listening to the student's oral reading of a selected section of the class text in order to note any miscues. Informal oral reading measures such as this can provide a teacher with important insight into a student's foundational reading skills (e.g., decoding ability, reading fluency), which are prerequisite for reading comprehension.
Question 15
15. A technology teacher regularly incorporates vocabulary self-awareness charts into each unit of study. At the beginning of a unit, the teacher has individual students read a list of key vocabulary words from the unit and rate each word from one to four. One means a student knows the word well and can demonstrate understanding of the word by providing both a definition and an example of the word used in context. Two means the student has some knowledge of the word and could produce either a definition or an example but not both. Three means the student has heard of the word but is not sure what it means or how to use it. Four means the student has never encountered the word before (or at least cannot recall having encountered it). Throughout the unit, the students continually update their word ratings as they add definitions and examples to their chart. The teacher's approach to instruction promotes students' knowledge of discipline-specific vocabulary primarily by developing the students':
- knowledge of morphology and etymology.
- orthographic knowledge and decoding skills.
- metacognitive skills and word consciousness.
- understanding of semantics and syntax.
Answer to question 15
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0004) Metacognition is the awareness of how one is thinking and learning as one works on a task. Research on what effective readers do indicates that metacognition plays an important role in reading comprehension. Research on vocabulary development indicates that metacognition plays an important role here as well. Word awareness, or word consciousness, contributes to students' motivation to learn new words and general interest in vocabulary development.
Correct Response: C. (Objective 0004) Metacognition is the awareness of how one is thinking and learning as one works on a task. Research on what effective readers do indicates that metacognition plays an important role in reading comprehension. Research on vocabulary development indicates that metacognition plays an important role here as well. Word awareness, or word consciousness, contributes to students' motivation to learn new words and general interest in vocabulary development.
Question 16
16. A technology teacher regularly reads aloud short, complex informational texts that are related to the current unit of study but are written above students' instructional reading levels. During reading, the teacher pauses frequently to use think-aloud and discussion to highlight new vocabulary, deconstruct syntactically complex sentences, and develop students' conceptual understanding of the text's content. The teacher's approach to read-alouds promotes students' content-area reading development primarily by:
- enhancing their ability to select and use comprehension strategies.
- building their academic language and background knowledge.
- helping them distinguish between oral and written language conventions.
- motivating them to use effective study and research strategies.
Answer to question 16
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0004) In this scenario, the teacher engages students in strategic, purposeful read-alouds to promote their ability to comprehend complex content-area texts. The teacher purposefully selects texts written above students' instructional reading levels and then scaffolds their comprehension through think-alouds and discussions, during which the teacher focuses specifically on academic language development (e.g., vocabulary, syntax) and concept development. Vocabulary knowledge and concept development are closely interrelated; discipline-specific vocabulary development involves concept learning, while concept learning supports academic vocabulary development. Both academic language knowledge and background knowledge play important roles in the comprehension of content-area texts.
Correct Response: B. (Objective 0004) In this scenario, the teacher engages students in strategic, purposeful read-alouds to promote their ability to comprehend complex content-area texts. The teacher purposefully selects texts written above students' instructional reading levels and then scaffolds their comprehension through think-alouds and discussions, during which the teacher focuses specifically on academic language development (e.g., vocabulary, syntax) and concept development. Vocabulary knowledge and concept development are closely interrelated; discipline-specific vocabulary development involves concept learning, while concept learning supports academic vocabulary development. Both academic language knowledge and background knowledge play important roles in the comprehension of content-area texts.
Question 17
17. When tightening a bolt that fastens the valve cover of an engine, a torque wrench has which of the following advantages over a simple ratchet wrench?
- It allows a greater force to be applied to the bolt.
- It provides a better fit with the head of the bolt.
- It reduces the likelihood of overtightening the bolt.
- It takes less effort to provide the same force to the bolt.
Answer to question 17
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0005) A torque wrench is used where the tightness of screws and bolts is critical. It allows the operator to measure the torque, or turning force, applied to the fastener so that it can be matched to the specifications for a particular application. There are a variety of internal mechanisms used in torque wrenches, including types of "clutches" that allow the wrench to slip when a particular torque has been reached, and wrenches with indicator dials that show the amount of torque applied.
Correct Response: C. (Objective 0005) A torque wrench is used where the tightness of screws and bolts is critical. It allows the operator to measure the torque, or turning force, applied to the fastener so that it can be matched to the specifications for a particular application. There are a variety of internal mechanisms used in torque wrenches, including types of "clutches" that allow the wrench to slip when a particular torque has been reached, and wrenches with indicator dials that show the amount of torque applied.
Question 18
18. A person uses a medical device that plugs into a wall socket. In order to use a deep cycle 12-volt battery, similar to a car battery, as a back-up in case of a power failure, the person would need which of the following pieces of equipment?
- a capacitor
- an inverter
- a transducer
- a step-up transformer
Answer to question 18
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0005) Twelve-volt batteries, such as deep cycle or car batteries, produce direct current (DC). Household appliances in the United States use alternating current (AC). To use a 12-volt battery to power an appliance during a power outage, it is necessary to convert the direct current to alternating current using a DC-AC converter, also known as an inverter.
Correct Response: B. (Objective 0005) Twelve-volt batteries, such as deep cycle or car batteries, produce direct current (D C). Household appliances in the United States use alternating current (A C). To use a 12-volt battery to power an appliance during a power outage, it is necessary to convert the direct current to alternating current using a D C - A C converter, also known as an inverter.
Question 19
19. Which of the following devices works by disconnecting a circuit when a leakage of current is detected because the current flowing through the live conductor does not equal the current returning through the neutral conductor?
- voltage meter
- circuit breaker
- ground fault interrupter
- fuse
Answer to question 19
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0005) A ground fault interrupter (GFI) is an electrical device that is built in to many electrical outlets, especially those that are located where they may come into contact with water. GFIs prevent electrical shocks by disconnecting the circuit whenever they detect that the electrical current is not balanced between the energized conductor and the return neutral conductor. Such a state indicates that there is a leakage of current that might lead to a lethal shock if it is grounded through a person's body. GFIs act more quickly than fuses or circuit breakers to shut off current to a device and are mandated by most building codes for electrical outlets in kitchens and bathrooms.
Correct Response: C. (Objective 0005) A ground fault interrupter (G F I) is an electrical device that is built in to many electrical outlets, especially those that are located where they may come into contact with water. G F Is prevent electrical shocks by disconnecting the circuit whenever they detect that the electrical current is not balanced between the energized conductor and the return neutral conductor. Such a state indicates that there is a leakage of current that might lead to a lethal shock if it is grounded through a person's body. G F Is act more quickly than fuses or circuit breakers to shut off current to a device and are mandated by most building codes for electrical outlets in kitchens and bathrooms.
Question 20
20. One type of a digital multimeter measures the current in a wire by placing a circular shaped clamp around a wire in a circuit. One advantage of this multimeter design is that it allows the user to measure current without disconnecting any wires. Which of the following is another important advantage of this type of multimeter over models without a clamp?
- It is less likely to be affected by stray EM fields.
- It can measure voltage in addition to current.
- It can be used for measuring very high currents.
- It produces more precise and accurate readings.
Answer to question 20
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0005) To measure current, the leads of a conventional multimeter must be inserted parallel with the circuit so that all of the current in the circuit flows through the meter. Not only can this be dangerous, it can only be done for circuits with very small currents, since high currents will damage the multimeter. The clamp operates by measuring the magnetic field surrounding a wire in the circuit. Since this does not require an electrical connection to the circuit, no current from the circuit flows through the meter and very large currents can be measured without risk of damage to the meter.
Correct Response: C. (Objective 0005) To measure current, the leads of a conventional multimeter must be inserted parallel with the circuit so that all of the current in the circuit flows through the meter. Not only can this be dangerous, it can only be done for circuits with very small currents, since high currents will damage the multimeter. The clamp operates by measuring the magnetic field surrounding a wire in the circuit. Since this does not require an electrical connection to the circuit, no current from the circuit flows through the meter and very large currents can be measured without risk of damage to the meter.
Question 21
21. In the circuit below, a 9 V battery, 12 Ω resistor, and a lamp are connected in series.
In the circuit below, a 9 volt battery, 12 ohm resistor, and a lamp are connected in series.
diagram has a battery, a lamp, and a 12 ohm resistor connected in series. A voltmeter is shown indicating the voltage drop across the lamp is 5 volts.
If the voltage drop across the lamp is 5 V, what is the resistance of the lamp in this circuit?
- 0.33 Ω0 point 33 ohms
- 3 Ω3 ohms
- 4 Ω4 ohms
- 15 Ω15 ohms
Answer to question 21
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0006) Since the voltage drop across the lamp is 5 V, the voltage drop across the resistor must be 4 V. This follows from the conservation of energy applied to a circuit: the sum of the voltage drops in a circuit must equal the voltage of the battery (9 V = 5 V + 4 V). Applying Ohms law (V = IR, where V = 4 volts, R = 12 ohms, and solving for I) to the resistor results in a current of I = 0.33 amperes. This same current is going through the lamp. Applying Ohms law to the lamp (V = IR, where V = 5 volts, I = 0.33 amperes, and solving for R) results in a resistance of 15 ohms.
Correct Response: D. (Objective 0006) Since the voltage drop across the lamp is 5 V, the voltage drop across the resistor must be 4 V. This follows from the conservation of energy applied to a circuit: the sum of the voltage drops in a circuit must equal the voltage of the battery (9 V = 5 V plus 4 V). Applying Ohms law (V = IR, where V = 4 volts, R = 12 ohms, and solving for I) to the resistor results in a current of I = 0 point 33 amperes. This same current is going through the lamp. Applying Ohms law to the lamp (V = IR, where V = 5 volts, I = 0.33 amperes, and solving for R) results in a resistance of 15 ohms.
Question 22
22. Which of the following uses a chemical source of energy to generate electricity?
- a geothermal power plant
- a coal-fired power plant
- an array of solar collectors
- a nuclear power plant
Answer to question 22
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0006) Coal-fired power plants extract energy from the rapid oxidation (i.e., burning) of carbon compounds. Oxidation involves the chemical breakdown of complex carbon molecules into simpler molecules (e.g., carbon dioxide), releasing energy in the process.
Correct Response: B. (Objective 0006) Coal-fired power plants extract energy from the rapid oxidation (i.e., burning) of carbon compounds. Oxidation involves the chemical breakdown of complex carbon molecules into simpler molecules (e.g., carbon dioxide), releasing energy in the process.
Question 23
23. A step-down transformer on a utility pole outside a house lowers the voltage supplied to the house. The transformer contains a primary coil and a secondary coil. Voltage is lowered in the secondary coil because the primary coil and secondary coil differ in the:
- number of windings in each of the two coils.
- resistance of the material used as wire in the two coils.
- resistance of the material used as wire in the two coils.
- frequency of the current in the wire of the two coils.
Answer to question 23
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0006) Transformers work on the principle that a changing magnetic field through a wire induces a voltage in the wire. Transformers consist of two wire coils wrapped around a common core material. Alternating current supplied to the primary coil creates a changing magnetic field in the core material. This changing field passes through the secondary coil. The field through each winding of the coil contributes to the induced voltage, so the greater the number of windings, the greater the voltage. If the secondary coil has a greater number of windings than the primary, the voltage is increased, creating a step-up transformer. If the secondary coil has fewer windings, the transformer is a step-down transformer.
Correct Response: A. (Objective 0006) Transformers work on the principle that a changing magnetic field through a wire induces a voltage in the wire. Transformers consist of two wire coils wrapped around a common core material. Alternating current supplied to the primary coil creates a changing magnetic field in the core material. This changing field passes through the secondary coil. The field through each winding of the coil contributes to the induced voltage, so the greater the number of windings, the greater the voltage. If the secondary coil has a greater number of windings than the primary, the voltage is increased, creating a step-up transformer. If the secondary coil has fewer windings, the transformer is a step-down transformer.
Question 24
24. Approximately how long will it take a 5 kW motor to lift a 200-kilogram mass to a height of 15 meters?
- 3.8 seconds
- 5.9 seconds
- 30 seconds
- 67 seconds
Answer to question 24
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0006) Power is the rate at which work is done. The work required to lift a mass m to a height h is the product of the weight of the mass and the height. The weight of a mass m is given by mg, where g is the acceleration due to gravity. The power is the rate at which the work is done, or . Solving this algebraically for t gives , using the fact that g = 9.8 m/s2,
m = 200 kg, h = 15 m, and P = 5,000 W gives t = 5.9 seconds.
Correct Response: B. (Objective 0006) Power is the rate at which work is done. The work required to lift a mass m to a height h is the product of the weight of the mass and the height. The weight of a mass m is given by mg, where g is the acceleration due to gravity. The power is the rate at which the work is done, or P equals W over T equals M G H over T. Solving this algebraically for t gives T equals M G H over P, using the fact that g equals 9 point 8 meters per second squared,
m equals 200 kilograms, h equals 15 m, and P equals 5,000 W gives t equals 5 point 9 seconds.
Question 25
25. The amount of electricity generated by the turbines of a hydroelectric plant depends most directly on which of the following characteristics of the reservoir behind the dam?
- the surface area of the reservoir
- the density of the water in the reservoir
- the depth of the water just behind the dam
- the volume of water in the reservoir
Answer to question 25
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0007) In fluid dynamics, head is a concept that relates the energy in an incompressible fluid to the height of an equivalent static column of that fluid. One factor that goes into determining the head behind a dam is the weight of the water, and hence the pressure it exerts at the bottom of the water column. The pressure that the water behind the dam exerts on the turbines in a hydroelectric plant helps determine the amount of electric power that the turbines can generate. Since the weight of the water is dependent on its depth, the pressure exerted on the turbines is highly dependent on the height of the water column behind the dam.
Correct Response: C. (Objective 0007) In fluid dynamics, start italics head end italics is a concept that relates the energy in an incompressible fluid to the height of an equivalent static column of that fluid. One factor that goes into determining the head behind a dam is the weight of the water, and hence the pressure it exerts at the bottom of the water column. The pressure that the water behind the dam exerts on the turbines in a hydroelectric plant helps determine the amount of electric power that the turbines can generate. Since the weight of the water is dependent on its depth, the pressure exerted on the turbines is highly dependent on the height of the water column behind the dam.
Question 26
26. Which of the following electrical devices operates on the principle of using a material with high resistivity to produce energy transformations?
- an electric space heater
- a telephone
- an LED lightbulb
- a computer hard drive
Answer to question 26
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0007) Resistivity is a measure of how strongly a material opposes the flow of electric current. For example, aluminum and copper are used for wiring because they have low resistivity. In contrast, tungsten has high resistivity. Many radiant space heaters use tungsten filaments. In metals that have high resistivity, energy may be released as heat or light, which makes these metals useful for applications such as incandescent lightbulbs or space heaters where the production of heat or light from electric current is desirable.
Correct Response: A. (Objective 0007) Resistivity is a measure of how strongly a material opposes the flow of electric current. For example, aluminum and copper are used for wiring because they have low resistivity. In contrast, tungsten has high resistivity. Many radiant space heaters use tungsten filaments. In metals that have high resistivity, energy may be released as heat or light, which makes these metals useful for applications such as incandescent lightbulbs or space heaters where the production of heat or light from electric current is desirable.
Question 27
27. A hydraulic lift used to raise a car in an auto repair shop relies on which of the following principles?
- Different liquids have different densities and different viscosities.
- Heat can be added to a liquid without causing it to expand.
- The speed of a flowing liquid depends on the diameter of the pipe.
- Forces applied to a liquid are transmitted without compressing the liquid.
Answer to question 27
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0007) A fundamental application of hydraulics is force multiplication in which a force applied to a small surface over a long distance is transmitted and multiplied to a larger surface over a shorter distance. The ability of a hydraulic system to multiply force in this manner depends on the fact that liquids are basically incompressible, so that all force is transmitted through the system and none is used to compress the liquid within the system.
Correct Response: D. (Objective 0007) A fundamental application of hydraulics is force multiplication in which a force applied to a small surface over a long distance is transmitted and multiplied to a larger surface over a shorter distance. The ability of a hydraulic system to multiply force in this manner depends on the fact that liquids are basically incompressible, so that all force is transmitted through the system and none is used to compress the liquid within the system.
Question 28
28. In a typical heat pump, flowing refrigerant is used to move heat from one region to another. This is accomplished by a repeating cycle of compressing and expanding a refrigerant, such as ammonia, between gaseous and liquid forms. Which of the following physics processes occurs when the refrigerant is allowed to expand?
- The refrigerant warms up and emits heat to its surroundings.
- The refrigerant warms up and absorbs heat from its surroundings.
- The refrigerant emits heat to its surroundings and cools its surroundings.
- The refrigerant absorbs heat from its surrounding and cools its surroundings.
Answer to question 28
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0007) A heat pump consists of a refrigerant, a compressor, a condenser, and an evaporator. Heat pumps can either cool or heat a region, and operate on a cycle of a refrigerant going from gas to liquid and from liquid to gas. The compressor uses energy, such as electricity, to compress the refrigerant from a gas to a liquid. When the refrigerant is allowed to expand and change from the liquid to the gas phase, it absorbs energy from its surroundings. This is because heat energy is needed to break the physical bonds that hold the refrigerant molecules together in the liquid phase. The refrigerant absorbs heat energy from its surrounding as it changes from a liquid to a gas and cools down.
Correct Response: D. (Objective 0007) A heat pump consists of a refrigerant, a compressor, a condenser, and an evaporator. Heat pumps can either cool or heat a region, and operate on a cycle of a refrigerant going from gas to liquid and from liquid to gas. The compressor uses energy, such as electricity, to compress the refrigerant from a gas to a liquid. When the refrigerant is allowed to expand and change from the liquid to the gas phase, it absorbs energy from its surroundings. This is because heat energy is needed to break the physical bonds that hold the refrigerant molecules together in the liquid phase. The refrigerant absorbs heat energy from its surrounding as it changes from a liquid to a gas and cools down.
Question 29
29. Wet or wet/dry sandpaper is used most often in which of the following situations?
- Coarse sanding is necessary to remove rough spots.
- Deep gouges are present in the surface to be sanded.
- The surface to be sanded chips and flakes easily.
- The finished job must have a very smooth surface.
Answer to question 29
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0008) Wet or wet/dry sandpaper allows the use of water or some other liquid that carries away grit particles that are removed by the sanding process. If these particles are not removed, they can build up in the sandpaper and leave behind scratches that ruin the surface. Thus, wet or wet/dry sandpaper is used when a smooth, scratch-free surface is desired.
Correct Response: D. (Objective 0008) Wet or wet/dry sandpaper allows the use of water or some other liquid that carries away grit particles that are removed by the sanding process. If these particles are not removed, they can build up in the sandpaper and leave behind scratches that ruin the surface. Thus, wet or wet/dry sandpaper is used when a smooth, scratch-free surface is desired.
Question 30
30. The use of a torque wrench allows a mechanic working on a vehicle to:
- tighten bolts to a measured amount depending on the specifications for their uses.
- remove stuck bolts whose threads have been stripped.
- apply a greater amount of force to tighten bolts than would be possible with an ordinary wrench.
- reach around corners and into tight spots to tighten bolts.
Answer to question 30
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0008) A torque wrench is usually a type of socket wrench, although other types of wrenches and torque screwdrivers are also produced. There are several different kinds of torque wrenches, but all measure the amount of torque, or twisting force, that is being applied to a bolt or nut. Some wrenches simply display the torque applied so that the amount of force is controlled by the operator, while others incorporate a clutch or other mechanism so that the wrench slips when the preset torque is reached. Torque wrenches are important in applications where bolts or other fasteners must be tightened according to precise specifications, for example, when overtightening a bolt would damage one of the parts that are being joined.
Correct Response: A. (Objective 0008) A torque wrench is usually a type of socket wrench, although other types of wrenches and torque screwdrivers are also produced. There are several different kinds of torque wrenches, but all measure the amount of torque, or twisting force, that is being applied to a bolt or nut. Some wrenches simply display the torque applied so that the amount of force is controlled by the operator, while others incorporate a clutch or other mechanism so that the wrench slips when the preset torque is reached. Torque wrenches are important in applications where bolts or other fasteners must be tightened according to precise specifications, for example, when overtightening a bolt would damage one of the parts that are being joined.
Question 31
31. Which of the following components of an automobile is primarily responsible for reducing the toxicity of the by-products of internal combustion that are released in the vehicle's exhaust?
- turbocharger
- catalytic converter
- fuel injectors
- manifold
Answer to question 31
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0008) Automobile exhaust contains several toxic compounds, including carbon monoxide, unburned hydrocarbons, and oxides of nitrogen. A catalytic converter uses specific catalysts to convert these compounds into less toxic substances. For example, an oxidizing reaction in a catalytic converter converts carbon monoxide and unburned hydrocarbons to carbon dioxide and water.
Correct Response: B. (Objective 0008) Automobile exhaust contains several toxic compounds, including carbon monoxide, unburned hydrocarbons, and oxides of nitrogen. A catalytic converter uses specific catalysts to convert these compounds into less toxic substances. For example, an oxidizing reaction in a catalytic converter converts carbon monoxide and unburned hydrocarbons to carbon dioxide and water.
Question 32
32. Compared with cast iron or steel automobile engine blocks, aluminum blocks are likely to:
- be less prone to warping because aluminum is a stronger and tougher material.
- run cooler because aluminum is a much better conductor of heat.
- be more efficient because aluminum cylinders have a lower coefficient of friction.
- provide higher gas mileage and better handling because aluminum is lighter in weight.
Answer to question 32
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0008) One trend in the automobile industry has been to replace smaller cast iron or steel engine blocks with cast aluminum blocks. Aluminum has less strength than cast iron or steel and may be more likely to warp or crack, so large blocks are usually still made of cast iron or steel. However, aluminum blocks are lighter than most cast iron or steel blocks and the lower weight allows an increase in gas mileage for the automobile. Also, since there is less weight over the front wheels, small cars with aluminum blocks provide better handling than those with cast iron or steel blocks.
Correct Response: D. (Objective 0008) One trend in the automobile industry has been to replace smaller cast iron or steel engine blocks with cast aluminum blocks. Aluminum has less strength than cast iron or steel and may be more likely to warp or crack, so large blocks are usually still made of cast iron or steel. However, aluminum blocks are lighter than most cast iron or steel blocks and the lower weight allows an increase in gas mileage for the automobile. Also, since there is less weight over the front wheels, small cars with aluminum blocks provide better handling than those with cast iron or steel blocks.
Question 33
33. Which of the following features of highway design helps increase the stability of an automobile as it travels around a curve?
- making the center higher than the edges to facilitate draining of water during rainstorms
- banking the highway to increase the amount of horizontal force that is transmitted to the ground
- widening the travel lane to allow the automobile more freedom to drift as it takes the curve
- roughening the surface texture of the highway to increase friction between the tires and road
Answer to question 33
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0009) An automobile traveling around a curve generates centripetal force that tends to keep the automobile going in a straight direction. The horizontal component of this force acts perpendicular to the highway and would tend to cause the car to roll. Banking the curve directs more of this component of force against the ground, helping to keep the car stable as it travels around the curve.
Correct Response: B. (Objective 0009) An automobile traveling around a curve generates centripetal force that tends to keep the automobile going in a straight direction. The horizontal component of this force acts perpendicular to the highway and would tend to cause the car to roll. Banking the curve directs more of this component of force against the ground, helping to keep the car stable as it travels around the curve.
Question 34
34. On an eighteenth-century fighting ship like Old Ironsides, cannon were mounted on tracks. When a cannon was fired, the cannon and its carriage would rebound backward on the track and have to be hauled back to its original position before being fired again. This example of Newton's third law best explains the method of propulsion of which of the following types of aircraft?
- glider
- prop-driven plane
- hot-air balloon
- jet plane
Answer to question 34
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0009) Newton's third law states that for every action there is an equal and opposite reaction. Thus, when the cannon is fired, the force (the action) that sends the cannonball forward causes the carriage to run backward on its track (the reaction). Jet engines operate by the same principle in which the discharge of hot gases from the engine (the action) provides the force to thrust the plane forward through the air (the reaction).
Correct Response: D. (Objective 0009) Newton's third law states that for every action there is an equal and opposite reaction. Thus, when the cannon is fired, the force (the action) that sends the cannonball forward causes the carriage to run backward on its track (the reaction). Jet engines operate by the same principle in which the discharge of hot gases from the engine (the action) provides the force to thrust the plane forward through the air (the reaction).
Question 35
35. Use the figure below to answer the question that follows.
Figure resembles a drawing of a teardrop tilted 90 degrees, such that the narrow end of the tear is facing left and the thick rounded end is on the right. Label which reads direction of movement of airplane, as well as a right arrow next to this label, are placed below the figure.
Which of the following best explains the primary reason why the airplane wing generates lift as it is moved through the air?
- Air flowing over the top of the wing moves faster than air below the wing, creating a pressure differential with lower pressure above the wing.
- Air striking obliquely across the bottom of the wing creates an equal and opposite force that pushes the wing up.
- Atmospheric pressure decreases with altitude and air is continually rising from the earth, both of which create pressure below the wing.
- The tapered shape of the wing creates turbulence as air flows over the wing, which increases air pressure below the wing.
Answer to question 35
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0009) The forward thrust of an airplane creates air movement in the opposite direction over and under the wing. Since the wing is curved, the distance from the front of the wing to the back of the wing is greater along the top than along the bottom. Therefore, the movement of air over the wing is faster on the top of the wing than it is on the bottom. This creates a pressure differential with lower pressure on the top of the wing and higher pressure on the bottom, which generates lift on the wing.
Correct Response: A. (Objective 0009) The forward thrust of an airplane creates air movement in the opposite direction over and under the wing. Since the wing is curved, the distance from the front of the wing to the back of the wing is greater along the top than along the bottom. Therefore, the movement of air over the wing is faster on the top of the wing than it is on the bottom. This creates a pressure differential with lower pressure on the top of the wing and higher pressure on the bottom, which generates lift on the wing.
Question 36
36. Which of the following best describes the primary action of a shock absorber in the suspension system of an automobile?
- resisting fast changes in the distance between the wheel and frame of the car
- providing a constant outward force between the wheel and the frame of the car
- adjusting the interior and exterior wheel speeds for different turning radii of the car
- maintaining a constant vertical alignment of the wheel perpendicular to the car.
Answer to question 36
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0009) A shock absorber is part of a car's suspension system. One end of a shock absorber is attached to the wheel, and the other to the car frame. A shock absorber works by forcing oil through very small passages as the shock absorber is compressed or expanded. Due to its viscosity, the oil provides increasing resistance as the speed of the compression or expansion increases. This slows frame motion by resisting fast changes in the distance between the wheel and the car frame and brings the motion of the car frame to a stop. During the process, kinetic energy of motion is dissipated as heat. Without shock absorbers, cars would continue to bounce up and down long after passing over a bump in the road.
Correct Response: A. (Objective 0009) A shock absorber is part of a car's suspension system. One end of a shock absorber is attached to the wheel, and the other to the car frame. A shock absorber works by forcing oil through very small passages as the shock absorber is compressed or expanded. Due to its viscosity, the oil provides increasing resistance as the speed of the compression or expansion increases. This slows frame motion by resisting fast changes in the distance between the wheel and the car frame and brings the motion of the car frame to a stop. During the process, kinetic energy of motion is dissipated as heat. Without shock absorbers, cars would continue to bounce up and down long after passing over a bump in the road.
Question 37
37. Use the diagram below to answer the question that follows.
Fluid is shown flowing up and out through the neck and through a connected tube wider than the neck. As the fluid flows out, it displaces a ball from just outside the neck.
Which of the following best describes the function of the hydraulic system component shown?
- maintaining the same viscosity and temperature throughout the fluid
- multiplying the force that the fluid exerts on other components
- preventing air from entering the main fluid chamber
- ensuring that the fluid can flow only in one direction
Answer to question 37
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0010) The diagram illustrates a check valve in a hydraulic system. As fluid flows up through the valve, the ball is forced away from the opening and the fluid is able to continue flowing. Any force that causes the fluid to reverse direction would cause the ball to drop into the opening, shutting it against any passage of fluid and maintaining the stability of the system.
Correct Response: D. (Objective 0010) The diagram illustrates a check valve in a hydraulic system. As fluid flows up through the valve, the ball is forced away from the opening and the fluid is able to continue flowing. Any force that causes the fluid to reverse direction would cause the ball to drop into the opening, shutting it against any passage of fluid and maintaining the stability of the system.
Question 38
38. Which of the following best describes the function of a camshaft in a four-stroke internal combustion engine?
- changing the up-and-down movement of the pistons to rotary movement that can be communicated to the drive shaft
- converting the intermittent pulses of energy transmitted to the crankshaft to continuous energy flow so that it can be stored in the flywheel
- opening and closing the cylinder intake and exhaust valves during each of the four strokes that make up a complete cycle
- adjusting the fuel injectors to produce the correct fuel-to-air mixture in the cylinders to match the demand for power
Answer to question 38
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0010) In a four-stroke internal combustion engine, the intake stroke draws fuel and air into the cylinder through the open intake port. The exhaust port is closed. In the compression stroke, the piston compresses the air-fuel mixture and both intake and exhaust ports are closed. In the power stroke, the mixture is ignited, driving the piston down the cylinder and both ports remain closed. In the exhaust stroke the spent air and fuel is expelled through the exhaust port and the intake port is closed. The camshaft is attached to the crankshaft by a timing belt or chain and opens and closes the valves covering the intake and exhaust ports at the proper time during the four-stroke cycle of the engine.
Correct Response: C. (Objective 0010) In a four-stroke internal combustion engine, the intake stroke draws fuel and air into the cylinder through the open intake port. The exhaust port is closed. In the compression stroke, the piston compresses the air-fuel mixture and both intake and exhaust ports are closed. In the power stroke, the mixture is ignited, driving the piston down the cylinder and both ports remain closed. In the exhaust stroke the spent air and fuel is expelled through the exhaust port and the intake port is closed. The camshaft is attached to the crankshaft by a timing belt or chain and opens and closes the valves covering the intake and exhaust ports at the proper time during the four-stroke cycle of the engine.
Question 39
39. The best explanation for how the coil springs of a vehicle work is that kinetic energy produced when the vehicle goes over a bump:
- impacts a small area represented by the spring and is then dispersed over a wider area on the frame of the vehicle.
- produces heat in the spring as the spring is compressed, which is released into the atmosphere as the spring expands.
- is dispersed into the roadway by the force exerted downward by the weight of the car compressing the spring.
- is stored as potential energy when the spring compresses and released when the spring expands after the bump is traversed.
Answer to question 39
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0010) It takes a great deal of force to compress an automobile coil spring. This force is provided by the kinetic energy of the weight of the car as it goes over a bump in the road. Since the spring will expand as soon as the force holding it back is released, the force compressing the spring is stored as potential energy. When the bump is traversed and the spring is no longer being compressed, the stored potential energy is released as kinetic energy as the spring expands.
Correct Response: D. (Objective 0010) It takes a great deal of force to compress an automobile coil spring. This force is provided by the kinetic energy of the weight of the car as it goes over a bump in the road. Since the spring will expand as soon as the force holding it back is released, the force compressing the spring is stored as potential energy. When the bump is traversed and the spring is no longer being compressed, the stored potential energy is released as kinetic energy as the spring expands.
Question 40
40. The primary function of an automobile battery is to provide power to start the motor. Once the motor is running, the charging system in a modern car supplies more than enough electricity to run the motor, the computer, the lights, and other accessories. This is true even at an idle. However, it is still recommended that the battery not be disconnected in a modern car while it is running. Which of the following is the most important reason for this recommendation?
- to assure that the battery is brought back to a full charge
- to avoid voltage spikes that could damage the computer
- to prevent a spark that could ignite gas fumes or hydrogen
- to maintain a ground connection to the motor and frame
Answer to question 40
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0010) The battery acts as a large capacitor in an automotive electrical system. Its high capacitance is a vital characteristic for its secondary function of maintaining a constant system voltage. With a damaged or missing battery, rapid voltage changes could make sensors unreliable or even damage one of the many computers embedded in a modern car.
Correct Response: B. (Objective 0010) The battery acts as a large capacitor in an automotive electrical system. Its high capacitance is a vital characteristic for its secondary function of maintaining a constant system voltage. With a damaged or missing battery, rapid voltage changes could make sensors unreliable or even damage one of the many computers embedded in a modern car.