Một vật dao động điều hòa với phương trình \(x = 2\cos \left( {2\pi t - \frac{\pi }{6}} \right)\;\left( {cm} \right).\) Xác định li độ của vật theo đơn vị cm ở thời điểm t = 2 s. (Làm tròn đến số thập phân thứ 2 sau giấu phẩy)

Đáp án:

 

Mark the letter A, B, C or D on your answer sheet to indicate the best arrangement of utterances or sentences to make a meaningful exchange of text in each of the following questions from 13 to 17.

a. Emma: I’m thinking of having a small party with friends.

b. Lisa: I prefer travelling, but I understand your choice.

c. Lisa: Why not go on a trip instead?

d. Lisa: How are you going to celebrate your birthday this year?

e. Emma: Parties are easier to plan, and I love spending time with friends.

Nhận định nào đúng với lớp Manti dưới?

Thế kỉ XI, nhà Lý tiến hành cuộc kháng chiến chống quân xâm lược Tống ở phòng tuyến

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the best answer to each of the questions from 36 to 42.

In the distance, an enormous, menacing-looking tornado can be seen. Luckily, the area has been evacuated and there is no one to be seen. Then, out of the blue, a few kilometres away a van appears and races down the road straight towards the tornado. Both in their twenties, Joe Hammond and his wife Emma are heading for it. Their purpose is to monitor various characteristics of a tornado, such as its speed, direction, and temperature. The storm chasers are planning to plant themselves directly in the path of the tornado to amass as much information as they can.

Joe and Emma are dedicated storm chasers. They began to chase storms as university students, and in recent years they have been travelling vast distances around the USA in their efforts to locate tornadoes. Bizarre as it may sound, they are not the only people to do it. During the tornado season, hundreds of people cross Tornado Alley, an area between South Dakota and Texas. Their vehicles are almost unrecognisable, as they are concealed underneath an assortment of electronic equipment and contain all manner of communication devices.

When asked why people are so fascinated by tornadoes, Joe said some tornado chasers relish the challenge, while others might just love the exhilaration of being in a treacherous situation. Some experienced chasers have even turned their hobby into a business and set up travel agencies offering tourists trips which guarantee a ringside view of the twisters. It seems, however, that people like Joe and Emma also make a pivotal contribution to the study of tornadoes.

The fact is, although there are about a thousand tornadoes in the USA each year, meteorologists still do not fully comprehend why they happen. This is partly because the research done by radars in laboratories is not as efficacious as mobile equipment deployed directly at the scene. Thus, some research meteorologists even go storm chasing themselves. It seems that the thrill, combined with a desire to understand nature, is the reason why people like Joe and Emma chase tornadoes.

(Adapted from Venture into First for Schools)

Which of the following can be the best title for the passage?

Read the following passage about education in Nepal and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40. 

A few years ago, amid a record drought, scientists noticed something odd. A few of California’s giant sequoias inside Sequoia and Kings Canyon National Parks were dying in ways no one had ever documented – from the top down. When researchers climbed into the canopies, they discovered that beetles had bored into a few branches. By 2019, at least 38 of the trees had died – not a large number, but "concerning because we’ve never observed this before,” says Christy Brigham, the park’s chief of resource management.

Scientists had assumed that stately sequoias, with their bug-repelling tannins, were immune to dangerous pests. Worried experts are investigating whether some mix of increased drought and wildfire, both worsened by climate change, have now made even sequoias susceptible to deadly insect invasions.

If so, these ancient sentinels would be just the latest example of a trend experts are documenting around the world: Trees in forests are dying at increasingly high rates—especially the bigger, older trees. According to a study in the journal Science, the death rate is making forests younger, threatening biodiversity, eliminating important plant and animal habitat, and reducing forests’ ability to store excess carbon dioxide generated by our consumption of fossil fuels. [A]

There is no single direct cause. Decades of logging and land clearing play a role, scientists say. But increasing temperatures and rising carbon dioxide from the burning of fossil fuels have significantly magnified most other causes of tree death. Scientists are documenting longer and harsher droughts, more severe outbreaks of insects and disease, and increasingly catastrophic wildfires.

With 60,000 known tree species on Earth, those shifts are playing out differently across the planet. In central Europe, for instance, “You don’t have to look for dead trees,” says Henrik Hartmann, with Germany's Max Planck Institute for Biogeochemistry. “They’re everywhere.” In one recent year, following a week of excessive heat, hundreds of thousands of beech trees dropped their leaves. Even in colder regions, “You get a couple of hot years and the forests are suffering,” says Hartmann. “There are individual species that are being driven beyond the threshold of what they can handle.” [B]

Just last year, massive fires marched through a dry Australia, smoldered across 7.4 million acres in northern Siberia, and focused the world’s attention on blazes in the Amazon.

The consequences of all these changes around the world are still being assessed. The first national look at tree mortality in Israel showed vast stretches disappearing, thanks largely to scorching heat and wildfires. [C] In a country largely blanketed by stone and sand, forests mean a great deal. Trees support nests for eagles and habitat for wolves and jackals. They hold soil with their roots. [D]

“We’re dealing with a very tough situation. It’s a race to the unknown,” says Tamir Klein at the Weizmann Institute of Science.

What does ‘these ancient sentinels’ in paragraph 3 refer to?

Trong giai đoạn 3, hóa chất \(\mathbf{X}\) được thêm vào thiết bị phản ứng số \(3\) và thu được sản phẩm \(\mathbf{Y}\), trong đó \(\mathbf{X}\) và \(\mathbf{Y}\) lần lượt là:

Không khí trong đất cung cấp O₂cho:

Tổ chức liên kết kinh tế khu vực ở nào có nhiều quốc gia châu Á tham gia nhất?

Hàm số $y=x^3-5x^2+7x-1$ đạt cực đại tại

Mark the letter A, B, C or D on your answer sheet to indicate the best arrangement of utterances or sentences to make a meaningful exchange or text in each of the following questions from 13 to 17.

a. Tom: I heard the Pine Valley trail is beautiful this time of year. Want to check it out?

b. Mia: Hey Tom, do you have any plans for the weekend?

c. Mia: Absolutely! What time do you want to leave?

d. Tom: Not yet! I was thinking about going hiking. What do you think?

e. Mia: That sounds fun! Do you have a specific trail in mind?

Cho hàm số $y=\sqrt{x+\frac{1}{x}}$. Giá trị nhỏ nhất của hàm số trên $(0;+\infty )$ bằng?

Một con lắc lò xo dao động điều hòa với chu kì $T$. Thời gian để nó thực hiện 5 dao động là

Bảng chân lí sau mô tả liên hệ logic giữa các đầu vào X₁, X₂, và đầu ra F của cổng logic

Chọn ý đúng: Theo công dụng kinh tế người ta chia tài nguyên thành các loại nào?

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