Một vật nhỏ hình cầu khối lượng m được treo vào lò xo nhẹ có độ cứng k. Vật dao động điều hoà theo phương thẳng đứng với phương trình \(x = 2\cos (10t - \frac{\pi }{6})\) (trong đó x tính bằng cm, t tính bằng s).Vận tốc của vật khi đi qua vị trí cân bằng là

Tác giả nào KHÔNG trưởng thành trong cùng thời kì với các tác giả khác?

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.

a. Sally: Watch out, Janna! That floor looks really slippery.

b. Janna: Oh, thanks for warning me, Sally. I’ll be extra careful.

c. Sally: Good idea. Better safe than sorry!

Nếu xét 4 cặp alen nằm trên 4 cặp NST thường khác nhau Aa, Bb, Dd, Ee. Số kiểu gen của P có thể là bao nhiêu kiểu khi chúng tạo được 4 kiểu giao tử?

Read the passage below and choose A, B, C or D.

Millions of people are using cellphones today. In many places, it is actually considered unusual not to use one. In many countries, cellphones are very popular with young people. They find that the phones are more than a means of communication - having a mobile phone shows that they are cool and connected.

The explosion in mobile phone use around the world has made some health professionals worried. Some doctors are concerned that in the future many people may suffer health problems from the use of mobile phones. In England, there has been a serious debate about this issue. Mobile phone companies are worried about the negative publicity of such ideas. They say that there is no proof that mobile phones are bad for your health.

On the other hand, medical studies have shown changes in the brain cells of some people who use mobile phones. Signs of change in the tissues of the brain and head can be detected with modern scanning equipment. In one case, a traveling salesman had to retire at young age because of serious memory loss. He couldn't remember even simple tasks. He would often forget the name of his own son. This man used to talk on his mobile phone for about six hours a day, every day of his working week, for a couple of years. His family doctor blamed his mobile phone use, but his employer's doctor didn't agree.

What is it that makes mobile phones potentially harmful? The answer is radiation. High-tech machines can detect very small amounts of radiation from mobile phones. Mobile phone companies agree that there is some radiation, but they say the amount is too small to worry about.

As the discussion about their safety continues, it appears that it's best to use mobile phones less often. Use your regular phone if you want to talk for a long time. Use your mobile phone only when you really need it. Mobile phones can be very useful and convenient, especially in emergencies. In the future, mobile phones may have a warning label that says they are bad for your health. So for now, it's wise not to use your mobile phone too often.

What does the word “They” in paragraph 2 refer to?

Read the following passage about managing change 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. 

Growing up in Athens, Greece, Lydia Borsi remembers feeling tested when she tried to deal with mental health issues. Borsi says she had been seeing a therapist for anxiety. But she notes that people in Greece do not openly discuss mental health issues, which also get little attention in general healthcare services. “It was a lot more secretive. And people thought that I was a lot more unique,” Borsi said.

That all changed in 2017 when she moved to the United States to study at the University of Rochester in Rochester, New York. “When I came here, I really liked that people were not afraid to speak up about mental health and say that it’s important,” she said. The university was very supportive of her needs and offered plenty of information. She also became involved with a school group called Active Minds that helps students deal with mental health issues. [A]

Then due to the spread of the novel coronavirus, the University of Rochester had to move all its classes and some of its mental health resources online. Luckily, Borsi was able to connect with a mental health expert outside the school, in the local community. [B]

But as many of her American friends returned home, Borsi was stuck. Greece had succeeded in limiting the spread of the virus within its borders, but flights there from the U.S. are barred until July. Also, the health crisis has put her plans to seek admission to medical school in Britain on hold. [C] And she is not alone.

[D] In April, Active Minds launched a survey of over 2,000 students at U.S. colleges and universities. The study found that over 80 percent of those asked said the coronavirus crisis had negatively affected their mental health. One in five said it has affected them severely.

Laura Horne, chief program officer at Active Minds, says the findings are especially troubling given that the crisis is only going to make it harder for colleges and universities to help these students. “Colleges and universities had to pivot rather quickly to respond to COVID-19 and figure out all facets of university life, including mental health services. Now they have to figure out how to communicate with students,” Horne said.

Frank Chen is a Houston, Texas-based psychiatrist who has worked with college-age young adults. He points out that individuals at that age are in an important stage of their mental development. And college can be a difficult experience for students with or without mental health issues, as they balance work, studies, and personal relationships. Adding a major world event, like the spread of the coronavirus, makes it very difficult to predict what the long-term psychological effects might be. “I don’t think that there’s another event in the history of the people who are alive now that can really measure up to this,” said Chen.

The word ‘barred’ in paragraph 4 is closest in meaning to

Việc không nắm vững hình thức ngữ âm của từ dễ gây đến hậu quả gì?

Cho \(A = ( - 2;5]\) và \(B = (m; + \infty )\). Tìm \(m \in \mathbb{Z}\) để \(A{\rm{\backslash }}B\) chứa đúng 5 số nguyên?

Ý nào dưới đây không phải là vai trò của tín dụng?

Trong CSDL music ở bảng ban_thu_am trong thẻ Indexes đang được hiết lập như hình dưới đây, em hãy quan sát hình và cho biết để xoá bỏ hết cùng lúc các thiết lập khoá trong thẻ Indexes ta nháy chuột vào nút nào?

Quá trình trao đổi chất của con người thải ra môi trường những chất nào sau đây?

Một máy phát điện xoay chiều có 100 vòng dây, diện tích mỗi vòng là 0,2 m². Nếu máy phát điện quay với tốc độ 1500 vòng/phút trong từ trường đều có cảm ứng từ B=0,1 T. 

Suất điện động cực đại sinh ra là bao nhiêu vôn (làm tròn kết quả đến chữ số hàng đơn vị)?

Điền vào chỗ trống.

Cho bảng sau:

CƠ CẤU DÂN SỐ THEO NHÓM TUỔI CỦA NƯỚC TA GIAI ĐOẠN 1999 – 2021

(Đơn vị: %)

(Nguồn: Kết quả toàn bộ Tổng điều tra dân số và nhà ở năm 1999, 2009, 2019;Niên giám thống kê Việt Nam năm 2022)

Căn cứ vào bảng trên, số dân trong nhóm tuổi 15 – 64 tuổi năm 2019 của nước ta là...........triệu người (Biết quy mô dân số nước ta năm 2019 là 96,5 triệu người).

(Làm tròn đến số thập phân thứ nhất)

Quá trình chuyển hóa năng lượng trong động cơ đốt trong là?

Cho mạch điện như hình vẽ.

Suất điện động  = 28V, điện trở trong r = 2Ω, R = 5Ω. Độ lớn của cường độ dòng điện trong mạch chính là

Tin học và máy tính là cơ sở của sự ra đời và phát triển của yếu tố nào?

1 gram electron có bao nhiêu hạt?

Read of the following leaflet and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 7 to 12.

Join Our Fitness Revolution

Are you ready to (7)________ your fitness game? 

At our gym, you’ll not only find state-of-the-art equipment but also a community that motivates and supports you. Some people come for weight training, while (8)______join for cardio classes. 

We offer various training (9)______, including yoga, Pilates, and strength building. (10)__________ personal training sessions, we have group classes to fit every schedule. 

Our trainers are (11)__________in the fields of fitness and health, dedicated to helping you achieve your goals. Gain a new (12)________of confidence, energy, and enthusiasm from your workouts! 

Don't wait to become the best version of yourself. Join us today!

Sự phân hóa của thiên nhiên nước ta theo chiều bắc - nam là do

Đặc trưng cơ bản nhất của cơ chế thị trường là gì?