Một con lắc lò xo nằm ngang gồm vật nhỏ khối l ượng 100 g, lò xo  nhẹ có hệ số đàn hồi 1 N/cm. Hệ số ma sát trượt giữa vật và mặt phẳng ngang là 0,5. Ban đầu vật được giữ ở vị trí lò xo dãn 5 cm rồi thả nhẹ, con lắc dao động tắt dần, lấy g = 10 m/s² Quãng đường vật nhỏ đi được kể từ lúc thả vật đến lúc tốc độ của nó triệt tiêu lần thứ 2 là ?         

Read the following passage and mark the letters A, B, C or D on your answer sheet to indicate the correct answer to each of the questions:

Scientists do not yet thoroughly understand just how the body of an individual becomes sensitive to a substance that is harmless or even wholesome for the average person. Milk, wheat, and egg, for example, rank among the most healthful and widely used foods. Yet these foods can cause persons sensitive to them to suffer greatly. At first, the body of the individual is not harmed by coming into contact with the substance. After a varying interval of time, usually longer than a few weeks, the body becomes sensitive to it, and an allergy has begun to develop. Sometimes it's hard to figure out if you have a food allergy, since it can show up so many different ways. Your symptoms could be caused by many other problems. You may have rashes, hives, joint pains, mimicking arthritis, headaches, irritability, or depression. The most common food allergies are to milk, eggs, seafood, wheat, nuts, seeds, chocolate, oranges, and tomatoes. Many of these allergies will not develop if these foods are not fed to an infant until her or his intestines mature at around seven months. Breast milk also tends to be protective. Migraines can be set off by foods containing tyramine, phenathylamine, monosodium glutamate, or sodium nitrate. Common foods which contain these are chocolate, aged cheeses, sour cream, red wine, pickled herring, chicken livers, avocados, ripe bananas, cured meats, many Oriental and prepared foods (read the labels!). Some people have been successful in treating their migraines with supplements of B-vitamins, particularly B6 and niacin. Children who are hyperactive may benefit from eliminating food additives, especially colorings, and foods high in salicylates from their diets. A few of these are almonds, green peppers, peaches, tea, grapes. This is the diet made popular by Benjamin Feingold, who has written the book “Why your Child is Hyperactive”. Other researchers have had mixed results when testing whether the diet is effective.

Question 38: The word "symptoms" is closest in meaning to______________.  

Read the following passage and mark the letters A, B, C or D on your answer sheet to indicate the correct answer to each of the questions:

Scientists do not yet thoroughly understand just how the body of an individual becomes sensitive to a substance that is harmless or even wholesome for the average person. Milk, wheat, and egg, for example, rank among the most healthful and widely used foods. Yet these foods can cause persons sensitive to them to suffer greatly. At first, the body of the individual is not harmed by coming into contact with the substance. After a varying interval of time, usually longer than a few weeks, the body becomes sensitive to it, and an allergy has begun to develop. Sometimes it's hard to figure out if you have a food allergy, since it can show up so many different ways. Your symptoms could be caused by many other problems. You may have rashes, hives, joint pains, mimicking arthritis, headaches, irritability, or depression. The most common food allergies are to milk, eggs, seafood, wheat, nuts, seeds, chocolate, oranges, and tomatoes. Many of these allergies will not develop if these foods are not fed to an infant until her or his intestines mature at around seven months. Breast milk also tends to be protective. Migraines can be set off by foods containing tyramine, phenathylamine, monosodium glutamate, or sodium nitrate. Common foods which contain these are chocolate, aged cheeses, sour cream, red wine, pickled herring, chicken livers, avocados, ripe bananas, cured meats, many Oriental and prepared foods (read the labels!). Some people have been successful in treating their migraines with supplements of B-vitamins, particularly B6 and niacin. Children who are hyperactive may benefit from eliminating food additives, especially colorings, and foods high in salicylates from their diets. A few of these are almonds, green peppers, peaches, tea, grapes. This is the diet made popular by Benjamin Feingold, who has written the book “Why your Child is Hyperactive”. Other researchers have had mixed results when testing whether the diet is effective.

Question: The phrase "set off" is closest in meaning to______________.          

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 18 to 25:

 The three phases of human memory are the sensory memory, the short-term memory, and the long-term memory. This devision of the memory into phases is based on the length of time of the memory.

 Sensory memory is instantaneous memory. It is an image or memory that enters your mind only for a short period of time; it comes and goes in under a second. The memory will not last longer than that unless the information enters the short-term memory.

 Information can be held in the short-term memory for about twenty seconds or as long as you are actively using it. If you repeat a fact to yourself, that fact will stay in your short-term memory as long as you keep repeating it. Once you stop repeating it, either it is forgotten or it moves into long term memory.

 Long-term memory is the huge memory tank that can hold ideas and images for years and years. Information can be added to your long-term memory when you actively try to put it there through memorization or when an idea or image enters your mind on its own.

Question: The expression “is based on” in the first paragraph could be best replaced by________

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 18 to 25:

 The three phases of human memory are the sensory memory, the short-term memory, and the long-term memory. This devision of the memory into phases is based on the length of time of the memory.

 Sensory memory is instantaneous memory. It is an image or memory that enters your mind only for a short period of time; it comes and goes in under a second. The memory will not last longer than that unless the information enters the short-term memory.

 Information can be held in the short-term memory for about twenty seconds or as long as you are actively using it. If you repeat a fact to yourself, that fact will stay in your short-term memory as long as you keep repeating it. Once you stop repeating it, either it is forgotten or it moves into long term memory.

 Long-term memory is the huge memory tank that can hold ideas and images for years and years. Information can be added to your long-term memory when you actively try to put it there through memorization or when an idea or image enters your mind on its own.

Question: The three phases of memory discussed in the pasage are differentiated according to________

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 18 to 25:

 The three phases of human memory are the sensory memory, the short-term memory, and the long-term memory. This devision of the memory into phases is based on the length of time of the memory.

 Sensory memory is instantaneous memory. It is an image or memory that enters your mind only for a short period of time; it comes and goes in under a second. The memory will not last longer than that unless the information enters the short-term memory.

 Information can be held in the short-term memory for about twenty seconds or as long as you are actively using it. If you repeat a fact to yourself, that fact will stay in your short-term memory as long as you keep repeating it. Once you stop repeating it, either it is forgotten or it moves into long term memory.

 Long-term memory is the huge memory tank that can hold ideas and images for years and years. Information can be added to your long-term memory when you actively try to put it there through memorization or when an idea or image enters your mind on its own.

Question: The best title for this pasage would be______

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 18 to 25:

 The three phases of human memory are the sensory memory, the short-term memory, and the long-term memory. This devision of the memory into phases is based on the length of time of the memory.

 Sensory memory is instantaneous memory. It is an image or memory that enters your mind only for a short period of time; it comes and goes in under a second. The memory will not last longer than that unless the information enters the short-term memory.

 Information can be held in the short-term memory for about twenty seconds or as long as you are actively using it. If you repeat a fact to yourself, that fact will stay in your short-term memory as long as you keep repeating it. Once you stop repeating it, either it is forgotten or it moves into long term memory.

 Long-term memory is the huge memory tank that can hold ideas and images for years and years. Information can be added to your long-term memory when you actively try to put it there through memorization or when an idea or image enters your mind on its own.

Question: According to the passage, when will information stay in your short-term memory?  

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 18 to 25:

 The three phases of human memory are the sensory memory, the short-term memory, and the long-term memory. This devision of the memory into phases is based on the length of time of the memory.

 Sensory memory is instantaneous memory. It is an image or memory that enters your mind only for a short period of time; it comes and goes in under a second. The memory will not last longer than that unless the information enters the short-term memory.

 Information can be held in the short-term memory for about twenty seconds or as long as you are actively using it. If you repeat a fact to yourself, that fact will stay in your short-term memory as long as you keep repeating it. Once you stop repeating it, either it is forgotten or it moves into long term memory.

 Long-term memory is the huge memory tank that can hold ideas and images for years and years. Information can be added to your long-term memory when you actively try to put it there through memorization or when an idea or image enters your mind on its own.

Question: According to the passage, which type of memory is the shortest?  

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answers:

American humor and American popular heroes were born together. The first popular heroes of the new nation were comic heroes, and the first popular humor of the new nation was the antics of its hero-clowns.

The heroic and the comic were combined in novel American proportions in popular literature. The heroic themes are obvious enough and not much different from those in the legends of other times and places: Achilles, Beowulf, Siegfried, Roland, and King Arthur. The American Davy Crockett legends repeat the familiar pattern of the old world heroic story: the pre-eminence of a mighty hero whose fame in myth has a tenuous basis in fact; the remarkable birth and precocious strength of the hero; single combats in which he distinguished himself against antagonists, both man and beast; vows and boasts; pride of the hero in his weapons, his dog, and his woman.

Davy Crockett conquered man and beast with a swaggering nonchalance. He overcame animals by force of body and will. He killed four wolves at the age of six. He hugged a bear to death; he killed a rattlesnake with his teeth. He mastered the forces of nature. Crockett's most famous natural exploit was saving the earth on the coldest day in history. First, he climbed a mountain to determine the trouble. Then he rescued all creation by squeezing bear-grease on the earth's frozen axis and over the sun's icy face. He whistled, "Push along, keep moving!" The earth gave a grunt and began moving.

Neither the fearlessness nor the bold huntsman's prowess was peculiarly American. Far more distinctive was the comic quality, all heroes are heroic; few are also clowns. What made the American popular hero heroic also made him comic. "May be", said Crockett, "you'll laugh at me and not at my book". The ambiguity of American life and the vagueness which laid the continent open to adventure, which made the land a rich storehouse of the unexpected, which kept vocabulary ungoverned and the language fluid----this same ambiguity suffused both the Crockett legends were never quite certain whether to laugh or to applaud, or whether what they saw and heard was wonderful, awful or ridiculous.

Question 50: The word "ambiguity" in the last paragraph is closest meaning to _______.

Cho đa giác đều có đỉnh. Chọn ngẫu nhiên đỉnh của đa giác đều, xác suất để đỉnh được chọn là đỉnh của một tam giác vuông không cân là           

Cho đa giác đều có đỉnh. Gọi là tập tất cả các tam giác có ba đỉnh là ba đỉnh của đa giác đã cho. Chọn ngẫu nhiên một tam giác thuộc tập xác suất để tam giác được chọn là một tam giác cân nhưng không phải là tam giác đều là