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Have you ever wondered why the whistle of a traveling, distant locomotive predicts its approach several yards before anyone actually sees it? Or why an oncoming ambulance's screaming siren is heard momentarily several feet before the ambulance comes into full view, before it passes you, and why its siren is still heard faintly well after the ambulance is out of sight?
What you are witnessing is a scientific phenomenon known as the Doppler Effect. What takes place is truly remarkable. In both of these instances, when the train or ambulance moves toward the sound waves in front of it, the sound waves are pulled closer together and have a higher frequency. In either instance, the listener positioned in front of the moving object hears a higher pitch. The ambulance and locomotive are progressively moving away from the sound waves behind them, causing the waves to be farther apart and to have a lower frequency. These fast-approaching modes of transportation distance themselves past the listener, who hears a lower pitch.
What is the main idea of the passage?
- A. Trains and ambulances produce specific sounds
- B. Low-frequency waves produce high-pitched sounds.
- C. High-frequency waves produce low-pitched sounds.
- D. The Doppler Effect explains why sound is heard more strongly initially and then faintly after a moving object has passed.
Correct Answer: D
Rationale: The main idea of the passage is to explain the phenomenon known as the Doppler Effect, which describes how the frequency of sound waves changes as a source of sound moves relative to an observer. The passage illustrates this with examples of a traveling train and ambulance. As the objects approach the listener, the sound waves are compressed, resulting in a higher frequency and a higher pitch heard by the observer. Conversely, as the objects move away, the sound waves are stretched, leading to a lower frequency and a lower pitch. Therefore, the correct answer is D, as it summarizes the key concept of the Doppler Effect and its impact on sound perception.
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Homophones
English is a vibrant, changing, dynamic language. It allows people to express their thoughts in diverse ways, as there are many synonyms and antonyms to choose from. The hardest part for the English speaker - or those learning English as a second language - is learning about homonyms. These are words that sound alike but are spelled different ways, with different meanings.
One example is "One". This word, spelled "one" means the numeral 1, an amount. If spelled "won," it means to be victorious. No wonder spelling is a difficult skill to master! Other homonyms encountered by the beginning English speaker are "to, two, too," "four, for, fore," "there, their, they're" and "son, sun" to name just a few. This is one reason that "Spell check" programs on word processing computers cannot be completely accurate, because the way a word is spelled depends on the context of the sentence. Proofreaders will always be in demand.
What conclusion can be drawn from the article?
- A. In order to master English, the student must learn about homonyms.
- B. Learning homonyms is optional for mastering English.
- C. Mastering English requires avoiding homonyms.
- D. Homonyms are not important for learning English.
Correct Answer: A
Rationale: The correct answer is A: 'In order to master English, the student must learn about homonyms.' The article clearly emphasizes the importance of learning about homonyms, which are words that sound alike but are spelled differently and have different meanings. Understanding homonyms is crucial for mastering English, as they can significantly impact the meaning of sentences. Therefore, to become proficient in English, one must grasp the distinctions between homonyms to communicate effectively and avoid misunderstandings.
Changing Time: I have a major problem with Daylight Saving Time (DST). I really wish they would abolish the practice of changing the time on us every year. 'Spring ahead, Fall back' should disappear from our language.
Although an early goal of DST was to reduce evening usage of incandescent lighting, formerly a primary use of electricity, modern heating and cooling usage patterns greatly differ, and research about how DST currently affects energy use is limited and often contradictory. The reason for the time shift has become irrelevant.
DST's occasional clock shifts present other challenges. They complicate timekeeping and can disrupt meetings, travel, billing, recordkeeping, medical devices, and heavy equipment. Many computer-based systems can adjust their clocks automatically, but this can be limited and error-prone, particularly when DST rules change.
I vote to abolish DST. Can I count on your vote?
What statement most accurately reflects the author's attitude about this subject?
- A. DST is an inconvenience and should end.
- B. Natural resources are saved by the use of DST.
- C. DST does not affect occupations that work with animals.
- D. Everyone should vote in the next election.
Correct Answer: A
Rationale: The correct answer is A: DST is an inconvenience and should end.
Rationale:
1. The author expresses a negative attitude towards DST by stating "I really wish they would abolish the practice of changing the time on us every year."
2. The author mentions various challenges and disruptions caused by DST, indicating it is viewed as an inconvenience.
3. The author's call to action to abolish DST further highlights their negative attitude towards it.
Summary:
Choice B is incorrect because the author does not mention saving natural resources as a reason to abolish DST. Choice C is incorrect as the author does not discuss the impact of DST on specific occupations. Choice D is unrelated to the author's attitude towards DST.
Lightning Strikes: The old wives' tale of "Lightning never strikes twice" has been proven untrue time and time again. Lightning forms from negative and positive charges within clouds and from the earth below. When these charges react with each other, the air between the cloud and the earth ionizes, which produces a lightning flash. Lightning is actually a series of multiple events consisting of a leader stroke of lightning, followed by as many as 40 smaller strokes of lightning. Being just split seconds apart, these strokes of lightning often reflect off the lining of the clouds.
Lightning rods that extend from above the roof to the ground protect buildings by forming a low resistance path for the lightning so that the lightning does not enter the building, but rather defuses as it penetrates the ground.
Some myths about lightning need to be explained. Lightning does strike tall buildings often, and during a particularly violent storm, a tall building may be hit by lightning several times. The safest place during a thunder and lightning storm is in a metal car or lying flat, face down, in the open, not under a tree as the myth suggests.
Many people believe that thunder and lightning are connected; however, this proves to be true only about 50% of the time, so if you're waiting for the clap of thunder, you're missing out on some exciting strokes of lightning!
Lightning causes injuries, deaths, and forest fires each year. However, some scientists reveal the positive aspects of lightning because it releases nitrogen into the atmosphere which the raindrops then deliver to earth to fertilize our soil.
When taking cover from lightning, you should
- A. go to the highest point in a tall building.
- B. stand in the doorway of a building.
- C. stand under a large tree with branches.
- D. get into a metal car or lie flat on the ground in the open.
Correct Answer: D
Rationale: The correct answer is D: get into a metal car or lie flat on the ground in the open. When taking cover from lightning, it is crucial to minimize your risk of being struck. Getting into a metal car provides protection as the metal shell of the car acts as a Faraday cage, directing the lightning around the vehicle and into the ground. Lying flat on the ground reduces your height and minimizes the risk of a direct strike. It is important to avoid standing in open areas, such as under a tree, as trees can attract lightning strikes. Standing in the doorway of a building is also unsafe as lightning can travel through conductive materials like metal door frames. Going to the highest point in a tall building is dangerous as tall structures are more likely to be struck by lightning. Therefore, the safest options are to get into a metal car or lie flat on the ground in the open to reduce the risk of being struck by lightning.
A BIT ABOUT BICYCLES
Today, bicycles are so common that it's hard to believe they haven't always been around. But two hundred years ago, bicycles didn't even exist, and the first bicycle, invented in Germany in 1818, was nothing like our bicycles today. It was made of wood and didn't even have pedals. Since then, however, numerous innovations and improvements in design have made the bicycle one of the most popular means of recreation and transportation around the world. In 1839, Kirkpatrick Macmillan, a Scottish blacksmith, dramatically improved upon the original bicycle design. Macmillan's machine had tires with iron rims to keep them from getting worn down. He also used foot-operated cranks like pedals, so his bicycle could be ridden at a quick pace. It didn't look much like a modern bicycle, though, because its back wheel was substantially larger than its front wheel. In 1861, the French Michaux brothers took the evolution of the bicycle a step further by inventing an improved crank mechanism. Ten years later, James Starley, an English inventor, revolutionized bicycle design. He made the front wheel many times larger than the back wheel, put a gear on the pedals to make the bicycle more efficient, and lightened the wheels by using wire spokes. Although this bicycle was much lighter and less tiring to ride, it was still clumsy, extremely top heavy, and ridden mostly for entertainment. It wasn't until 1874 that the first truly modern bicycle appeared on the scene. (14) Invented by another Englishman, H.J. Lawson, the "safety bicycle" would look familiar to today's cyclists. This bicycle had equal-sized wheels, which made it less prone to toppling over. Lawson also attached a chain to the pedals to drive the rear wheel. With these improvements, the bicycle became extremely popular and useful for transportation. Today they are built, used, and enjoyed all over the world.
What has been added to the basic design of the bicycle?
- A. Gears and hand-operated brakes
- B. Electric motors and GPS systems
- C. Air conditioning and heated seats
- D. Folding frames and built-in speakers
Correct Answer: A
Rationale: The correct answer is A: Gears and hand-operated brakes. Over the years, the basic design of the bicycle has evolved through various innovations and improvements. Gears and hand-operated brakes were added to enhance the efficiency, speed, and safety of bicycles. These additions have significantly contributed to making bicycles more versatile and practical for both recreation and transportation purposes. Electric motors and GPS systems, air conditioning and heated seats, as well as folding frames and built-in speakers are not traditional features found in the basic design of bicycles.
Subjective exams measure your ability in several areas. Besides recall information, you must be
able to realize content logically and intelligently express yourself in a clearly understood manner. Subjective test provide opportunity for students to show their broad knowledge of a subjective
area. Answers may be in the form of paragraphs or lengthy essays. When your review for an essay exam, concentrate on main ideas rather than details. Since essay tests are less to a few questions, they are likely to deal with more important ideas of a subject. Prepare a list of question you think might be asked. Write an answer to each of your questions. Rather than writing complete sentence down your thoughts in outline form. Doing so will help
you organize the information so that you can express yourself clearly.
When you take the test, read through all the questions before you start to write. Allot time for each question, spending more time for questions worth the most points. Read each question carefully to determine exactly what they are asked. Pay attention to words such as define, illustrate, explain, list, compare, and contrast. Each work requires a different type of response. Write a brief outline of your answer on scrap paper or the back of the test. Make sure you include all the important ideas that are within the limits of the question. In other words, do not write more than is asked for each answer. When you write your answer, keep it specific and as brief as possible. In the introductory sentence it is often helpful to make a general statement that includes
important points addressed in each question. Such a topic sentence serves as a framework for your answer. Then use your outline to develop the main point and subtopics. Add substance to
your answer by including as many facts as possible to support your answer.
Check your paper before you submit it. Look for mistakes in grammar, spelling, sentence
structure, and punctuation. Unless you are certain an answer is wrong, do not change it. Your answer is an educated guess and is usually your best chance of answering correctly.
From the article, the reader can conclude that a test containing true-false questions is called what?
- A. Subjective
- B. Rejective
- C. Objective
- D. Detective
Correct Answer: C
Rationale: The correct answer is C: 'Objective.' The article distinguishes between subjective and objective tests. Objective tests, such as those containing true-false questions, have definitive answers that are either true or false. These questions are considered objective because they are not open to interpretation and are designed to measure specific knowledge or facts. On the other hand, subjective tests, as mentioned in the article, involve essay questions where responses are more interpretive and open-ended. Therefore, based on the information provided, the appropriate term for a test containing true-false questions is 'Objective.'