Một anten radar phát ra những sóng điện từ đến vật đang chuyển động về phía radar. Thời gian từ lúc anten phát sóng đến lúc nhận sóng phản xạ từ vật trở lại là $80\mu \text{s}$ . Sau hai phút, đo lần thứ hai, thời gian từ lúc phát đến lúc nhận lần này là  $76\mu \text{s}$. Tính tốc độ trung bình của vật. Coi tốc độ c ủa sóng điện từ trong không khí bằng  $3\cdot {10}^8\text{ m}/\text{s}$.

Sản phẩm của quá trình lên men ethylic là gì?

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

[I] Sperm whales are fascinating creatures. [II] They possess the biggest brain of any species, six times larger than a human’s, which scientists believe may have evolved to support intelligent, rational behavior. [III] They’re also highly social and capable of making decisions as a group. [IV] But there’s also a lot we don’t know about them, including what they may be saying to one another when communicating with a system of short clicks, known as codas.

Now, new research published in Nature Communications today suggests that sperm whales’ communication is actually much more expressive and complicated than was previously thought. A team of researchers led by Pratyusha Sharma at MIT’s Computer Science and Artificial Intelligence Lab (CSAIL) working with Project CETI, a nonprofit focused on using AI to understand whales, used statistical models to analyze whale codas and managed to identify a structure to their language that’s similar to features of human language. Their findings represent a tool future researchers could use to decipher not just the structure but the actual meaning of whale sounds.

For the study, the researchers examined recordings of 8,719 codas from around 60 whales collected by the Dominica Sperm Whale Project between 2005 and 2018, using a mix of AI algorithms for pattern recognition and classification. The AI then turned the clicks within the coda data into a new kind of data visualization called an exchange plot, revealing that some codas featured extra clicks. These extra clicks, combined with variations in the duration of their calls, appeared in interactions between multiple whales, which they say suggests that codas can carry more information and possess a more complicated internal structure than we had previously believed.

The team’s next step is to build language models of whale calls and to examine how those calls relate to different behaviors. They also plan to work on a more universal system that could be used across species, says Sharma. Taking a communication system we know nothing about, working out how it encodes and transmits information, and slowly beginning to understand what’s being communicated could have many purposes beyond whales. “I think we’re just starting to understand some of these things,” she says. “We’re very much at the beginning, but we are slowly making our way through.”

Where in paragraph 1 does the following sentence best fit?

They demonstrate a high level of sociability and are capable of collective decision – making.

Thông tin có tính chất nào sau đây với vai trò là ý nghĩa?

Vì sao cần tiêu dùng hợp lí, có kế hoạch?

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 following questions.

Taking Home the World Cup

Standing just 36 centimeters tall, the FIFA World Cup Trophy symbolizes the pinnacle of football achievement.  Every four years, teams worldwide compete for it, but no one ever takes the trophy home. Made of 18-carat gold, the original trophy remains under FIFA's protection, with winners receiving only a replica. This measure safeguards it from theft, as the trophy has been stolen twice in its history.

The original trophy was made by a French sculptor, Abel LaFleur, and was called the “Jules Rimet Cup,” in honor of the founder of the World Cup tournament. Sometime during the first three World Cup events (1930, 1934, and 1938), the name changed to simply the “World Cup.” Then during World War II, not much was seen or heard of the trophy. It was being kept hidden in a shoe box under the bed of Dr. Ottorino Barassi, the Italian vice-president of FIFA, to prevent it from falling into the hands of the Nazi army. In 1966, the Cup was stolen during a public showing of the trophy prior to the World Cup tournament in England. Luckily, it was found a short time later, none the worse for wear, in a trash container by a little dog named Pickles. Four years later, Brazil earned permanent possession of the original trophy by winning its third World Cup title. Unfortunately, the trophy was stolen a second time in 1983 and was never recovered. The Brazilian Football Association had to have a duplicate trophy made.

(I) After the first trophy became the possession of Brazil’s football association, a new World Cup Trophy for FIFA was designed by an Italian artist, Silvio Gazzaniga, in 1974. (II) This trophy cannot be won outright, but remains in the possession of FIFA, and rest assured they are watching it very closely. Today, World Cup winners are awarded a replica of the trophy that is gold-plated, rather than solid gold like the real one. (III) Gazzaniga’s World Cup trophy weighs almost five kilograms. (IV) Its base contains two layers of a semi-precious stone called malachite, and has room for seventeen small plaques bearing the names of the winning teams---enough space to honor all the World Cup champions up to the year 2038. After that, a new trophy will have to be made.

Which of the following best summarizes paragraph 3?

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. Finally, difficulties in communication and forming genuine connections due to social media and technology dependence are common among teens.

b. Additionally, cyberbullying and online harassment present significant challenges in the digital age.

c. Teens often face various social challenges.

d. Firstly, peer pressure can lead to risky behaviors such as substance abuse, smoking, or involvement in harmful activities.

e. Moreover, mental health issues, including anxiety and depression, are prevalent among teenagers due to academic stress or social pressures.

Đâu là đặc điểm nổi bật của vùng kinh tế Kiu-xiu?

Đường thẳng \(d\) đi qua điểm \(M\left( { - 2;1} \right)\) và vuông góc với đường thẳng \(\Delta :\left\{ \begin{array}{l}x = 1 - 3t\\y = - 2 + 5t\end{array} \right.\) có phương trình tham số là?

Khi cho lai giữa cây có kiểu hình hoa đỏ, đài ngã với cây có kiểu hình hoa trắng, đài cuốn, F₁ thu được toàn cây có kiểu hình hoa đỏ, đài ngã. Cho một cây F₁ tự thụ phấn, F₂ thu được 4 kiểu hình, trong đó kiểu hình hoa đỏ, đài cuốn chiếm 9%. Kết luận nào sau đây là không đúng?

Luận cương chính trị tháng 10 năm 1930 của Đảng Cộng sản Đông Dương có hạn chế về nhiệm vụ cách mạng là do chưa

Vai trò của việc lập kế hoạch tài chính cá nhân là gì?

Read the following passage about peer pressure and mark the letter A, B, C, or D to indicate the best answer to each of the following questions from 23 to 30.

Peer Pressure Among Youth

    Peer pressure can be particularly prevalent among teenagers, who are at a vulnerable stage of development and seeking their identity. It is a powerful force that can significantly impact the thoughts, actions, and behaviors of teenagers. During adolescence, individuals strive for acceptance and belonging, making them particularly susceptible to the influence of their peers. Understanding the nature of peer pressure and its effects is essential for supporting teenagers in navigating this challenging aspect of their social lives.

    One aspect of peer pressure is the pressure to conform to the norms and expectations of a social group. Teenagers may feel compelled to adopt certain behaviors, preferences, or attitudes to fit in and avoid social rejection. This conformity can range from relatively harmless choices, such as fashion trends, to more concerning behaviors, such as substance abuse or risky activities.

    Peer pressure can manifest in both explicit and implicit ways. Direct peer pressure involves explicit requests, invitations, or demands from peers to engage in specific actions or behaviors. Indirect or implicit peer pressure, on the other hand, is more subtle and involves observing others’ behaviors and feeling pressured to conform without any explicit requests. This type of pressure can be equally influential and difficult for teenagers to navigate.

    It is important to note that peer pressure can have positive or negative implications. Positive peer pressure can motivate teenagers to engage in healthy behaviors, such as participating in sports, pursuing academic goals, or engaging in community service. However, it can lead to risky or harmful behaviors, such as substance abuse, delinquency, or academic underachievement.

    Parents, educators, and mentors play a crucial role in helping teenagers navigate peer pressure. By fostering open and supportive relationships, adults can provide a safe space for teenagers to discuss their experiences and concerns. Promoting critical thinking, assertiveness skills, and self-confidence can empower teenagers to resist negative peer

pressure and make independent, healthy choices.

(Adapted from Peer Pressure: Its Influence on Teens and Decision Making)

In which paragraph does the writer explain the different forms of peer pressure?

Nội dung nào dưới đây không có trong học thuyết tế bào?

Cho α là góc tù. Khẳng định nào sau đây là đúng?

Việc khai thác tài nguyên nhờ công nghệ có thể dẫn đến

Toàn bộ các khoản thu, chi của Nhà nước được dự toán và thực hiện trong một khoảng thời gian nhất định được gọi là gì?

Với một quần thể thực vật ở thế hệ xuất phát (P) đều mang kiểu gen Aa. Quần thể tiến hành tự thụ phấn bắt buộc qua bốn thế hệ, tính theo lí thuyết, tỉ lệ kiểu gen aa ở thế hệ F₄ là bao nhiêu?