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Doppler Effect
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.
Which sound waves have a higher pitch?
- A. Those waves that are closer together
- B. Those waves that are farther apart
- C. Those waves that travel a long distance
- D. Those waves that travel a short distance
Correct Answer: A
Rationale: The correct answer is A: 'Those waves that are closer together.' In the Doppler Effect, when a source of sound moves towards a listener, the sound waves are compressed, resulting in a higher frequency and therefore a higher pitch. Conversely, when the source moves away from the listener, the waves are stretched, leading to a lower frequency and a lower pitch. This phenomenon explains why the whistle of a locomotive or the siren of an ambulance changes pitch as it approaches and then moves away. Therefore, the sound waves that are closer together have a higher pitch.
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Let's Go to the Circus
Everyone loves a circus! The bright lights, fanciful costumes, and fierce wild animals delight and entertain folks of all ages. The circus calls to the child in each one of us. Ernest Hemingway wrote that it "is the only ageless delight that you can buy for money..."
"Circus" is a magic word inspiring all sorts of exciting, colorful images. It's a theater of mind-boggling feats, elephants thundering around the rings, horses dancing, clowns cavorting and the sequins glittering under the lights.
There are historical references to animal displays and athletic competitions from the earliest days of civilization. The Romans were famous for their extravaganzas in the Coliseum. The shows we see today cannot compare to those great spectacles, but all who go to a circus enjoy the experience. It allows us all to be a child again and watch in awe as the athletes perform on the high wire or control the savage beasts in the center ring.
What does 'cavorting' mean in the second paragraph?
- A. Making balloon animals
- B. Hitting each other
- C. Squirting water at the audience
- D. Running and jumping
Correct Answer: D
Rationale: In the context of the passage, 'cavorting' generally means to jump or leap around in a lively or playful way. It describes clowns moving about energetically in a fun and playful manner, aligning with the idea of running and jumping. The word 'cavorting' adds to the colorful and exciting imagery of the circus performance described in the text.
The water cycle, also known as the hydrologic cycle, is a continuous process by which water circulates through the Earth's atmosphere, oceans, and land. This cycle is essential for supporting all forms of life and maintaining the Earth's climate. Water undergoes various changes in state—evaporating from the surface, condensing in the atmosphere, and precipitating back to the surface. At its start, the sun heats up water in rivers, lakes, and oceans, causing it to evaporate and rise into the atmosphere as vapor. Once in the atmosphere, this vapor cools and condenses into clouds. Over time, these clouds get heavy and release precipitation in the form of rain, snow, or sleet, which falls back to the Earth's surface. Some of this precipitation collects in bodies of water, while some seeps into the soil, replenishing groundwater supplies. Additionally, some water returns to the atmosphere through transpiration, a process where water is released from plants. The cycle is critical not only for water distribution but also for transporting nutrients and purifying water naturally through filtration as it flows through different layers of the Earth's surface.
What is the primary function of the water cycle?
- A. To generate energy
- B. To transport nutrients
- C. To support life and maintain climate
- D. To produce oxygen
Correct Answer: C
Rationale: The primary function of the water cycle, also known as the hydrologic cycle, is to support life and maintain climate. The water cycle is essential for all forms of life as it ensures the distribution of water, replenishment of groundwater supplies, and natural purification of water through filtration. Furthermore, the cycle plays a crucial role in regulating the Earth's climate by influencing temperature and weather patterns. While energy generation, nutrient transportation, and oxygen production are important processes, they are not the primary function of the water cycle.
Health Care's Numbers Game: The game of health care is a risky one. Today emergency rooms are acting as primary care physicians for thousands of patients. This trend produces a vicious cycle of hospitals raising emergency room costs and passing that increase along to paying patients, who in turn pass it along to insurance companies, who in turn raise rates so even more people cannot afford the premium or the co-payment.
For years, indigent people have used emergency rooms for very minor illnesses rather than seeing an outside doctor, but now emergency rooms are seeing people with insurance, but who cannot afford the co-payment or the deductible for the office visit.
If we don't change the way the healthcare game is played, we're all going to lose.
According to the passage, why are more and more people using emergency rooms for minor illnesses?
- A. Patients want to continue the cycle of healthcare already established.
- B. The insurance companies require hospital visits for all illnesses.
- C. The doctors in emergency rooms are more skilled.
- D. They cannot afford the co-payment or deductible required by insurance.
Correct Answer: D
Rationale: The correct answer is D: They cannot afford the co-payment or deductible required by insurance. The passage explains that more people are using emergency rooms for minor illnesses because they cannot afford the co-payment or deductible for an office visit. This is supported by the statement that "emergency rooms are seeing people with insurance, but who cannot afford the co-payment or the deductible for the office visit." This directly links the financial barrier of affording the co-payment or deductible to the increased use of emergency rooms.
Choices A, B, and C are incorrect because they are not supported by the passage. Choice A suggests that patients want to continue the cycle of healthcare, which is not mentioned in the passage. Choice B states that insurance companies require hospital visits for all illnesses, which is not mentioned either. Choice C claims that doctors in emergency rooms are more skilled, which is also not supported by the passage.
People of Hispanic origin were on the North American continent centuries before settlers arrived
from Europe in the early 1600s and the thirteen colonies joined together to form the United
States in the late 1700s. The first census of the new nation was conducted in 1790, and counted about four million people, most of whom were white. Of the white citizens, more than 80%
traced their ancestry back to England. There were close to 700,000 slaves and about 60,000 "free Negroes". Only a few Native American Indians who paid taxes were included in the census count, but the total Native American population was probably about one million. By 1815, the population of the United States was 8.4 million. Over the next 100 years, the
country took in about 35 million immigrants, with the greatest numbers coming in the late 1800s and early 1900s. In 1882, 40,000 Chinese arrived, and between 1900 and 1907, there were more
than 30,000 Japanese immigrants. But by far, the largest numbers of the new immigrants were
from central, eastern, and southern Europe. An enormous amount of racial and ethnic assimilation has taken place in the United States. In 1908, play-write Israel Zangwill first used the term "melting pot" to describe the concept of a place where many races melted in a crucible and re-formed to populate a new land. Some years during the first two decades of the 20th century, there were as many as one million new
immigrants per year, an astonishing 1 percent of the total population of the United States.
In 1921, however, the country began to limit immigration, and the Immigration Act of 1924
virtually closed the door. The total number of immigrants admitted per year dropped from as many as a million to only 150,000. A quota system was established that specified the number of
immigrants that could come from each country. It heavily favored immigrants from northern and western Europe and severely limited everyone else. This system remained in effect until 1965, although after World War II, several exceptions were made to the quota system to allow in
groups of refugees.
Which of the following can be inferred from the passage?
- A. Preserving a developing 'American' culture was a major factor leading to the introduction of the quota system.
- B. Racial and ethnic assimilation did not occur as planned.
- C. Racial and ethnic tensions would have increased if the quota system had not been introduced.
- D. The quota system was introduced to limit population growth.
Correct Answer: A
Rationale: The correct answer is A. The passage discusses the implementation of the quota system in 1924 which heavily favored immigrants from northern and western Europe. This preference for specific regions suggests that preserving a developing 'American' culture, which was predominantly influenced by these regions, was a major factor leading to the introduction of the quota system. The passage does not indicate that racial and ethnic assimilation did not occur as planned, nor does it directly mention an increase in tensions if the quota system had not been introduced. Additionally, the quota system was not introduced to limit population growth but rather to control and regulate the influx of immigrants from different regions.
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.'