Hai dao động điều hòa có phương trình lần lượt là x1=3cos(2πt+2π) (cm) và x2=2cos(2πt+3π) (cm). Nhận định nào dưới đây là đúng?
Hãy suy nghĩ và trả lời câu hỏi trước khi xem đáp án
- Pha của dao động 1 là $\varphi_1 = 2\pi t + \dfrac{\pi}{2}$
- Pha của dao động 2 là $\varphi_2 = 2\pi t + \dfrac{\pi}{3}$
$\Delta \varphi = \varphi_1 - \varphi_2 = (2\pi t + \dfrac{\pi}{2}) - (2\pi t + \dfrac{\pi}{3}) = \dfrac{\pi}{2} - \dfrac{\pi}{3} = \dfrac{\pi}{6} > 0$
Vậy dao động 1 sớm pha hơn dao động 2 một góc $\dfrac{\pi}{6}$. Do đó, dao động 1 sớm pha hơn dao động 2.
Câu hỏi liên quan
Read the following passage about the cultural diversity 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 1 to 10.
[I] In today's globalized world, cultural diversity has become a fundamental aspect of many societies. [II] Many countries are experiencing increasing levels of migration. [III] With the rise of immigration and the blending of traditions, people from various cultural backgrounds are now living side by side in cities across the globe. [IV]
One of the key advantages of cultural diversity is the richness that it adds to a society. Different cultures introduce unique viewpoints, foods, languages, and traditions, which help people broaden their understanding of the world. In schools and workplaces, cultural diversity fosters creativity and innovation, as individuals from different backgrounds approach problems in innovative ways. However, there are also challenges associated with living in culturally diverse communities. Misunderstandings and communication barriers can arise when people are unfamiliar with each other's customs and values. To address these issues, societies must encourage cultural sensitivity and create opportunities for cross-cultural exchange.
Governments and institutions around the world are beginning to implement policies that promote inclusion and respect for cultural differences. By celebrating diversity through events, education, and media representation, communities can create environments where people feel valued regardless of their background. Ultimately, embracing cultural diversity helps to build more peaceful and harmonious societies.
Which of the following is TRUE according to the passage?
Trong phát triển kinh tế, sinh học có vai trò gì?
Mang có ở những loài động vật nào dưới đây?
Read thefollowing passage and mark the letter A, B, C or D on your answer sheet to indicate the option that bestfits each of the numbered blanksfrom 18 to 22.
Peer pressure, (18) ________, can have both positive and negative effects. For instance, when surrounded by motivated peers, (19) ________. Positive peer pressure can be a great motivator, as peers who excel in academics or extracurricular activities can inspire others to follow suit. However, peer pressure can also lead to negative outcomes. The influence of friends who engage in risky behaviors, such as skipping school or using substances, can encourage others to make poor decisions. Studies have shown that teenagers are more likely to take risks in the presence of their peers because they feel more confident when surrounded by others.
While peer pressure is often associated with negative behavior, (20) ________. For example, students may be encouraged to excel in their studies or participate in volunteer activities due to the positive influence of their peers. However, it is important to develop strong decision-making skills and self-confidence (21) ________.
Parents and educators play a key role in helping young people navigate peer pressure. By teaching young people how to recognize both positive and negative peer pressure, and how to make independent, thoughtful decisions, parents and educators can help ensure that students thrive in a healthy, supportive environment. Encouraging open communication, providing advice on how to stay true to one's values, and helping students develop self-confidence are all crucial aspects of this process.
In conclusion, peer pressure is a powerful influence. (22) ________, teenagers can succeed and grow in a positive social environment.
- Phát biểu nào sau đây không đúng với lớp Manti trên?
Vỏ Trái Đất ở lục địa có độ dày là bao nhiêu?
Nội dung nào sau đây phản ánh đúng vai trò của Sử học đối với công tác bảo tồn và phát huy giá trị di sản?
Cho góc \(x\left(0^{\circ} \leq x \leq 180^{\circ}\right)\) thỏa mãn \(\cos x=\frac{1}{4}\). Giá trị của \(P=\frac{\tan ^{2} x-\tan x+3 \cot x}{\frac{1}{2 \cos x}-5 \tan x+30 \cot ^{2} x}\) là
Read the following passage about food addiction 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.
Few people would disagree that one of the world's most popular dishes is pizza. Twenty-two-year-old Zack certainly wouldn't. He would eat a variety of pizza-based items, including homemade pizza, precooked microwave pizza, and even pizza leftovers from the night before. He was consuming 800kg of pizza a year. As a child, Zack had eaten a wide variety of food. But he became addicted to pizza when he started secondary school. American school meals have often been criticised for the large amount of fast food present on the menu, and pizza is the star dish. Zack even spent all his pocket money on slices of pizza.
Naturally, Zack's family worried about his high-calorie, low-vitamin diet. So did Zack. In an attempt to break his addiction, Zack agreed to appear on a TV programme called Freaky Eaters. Its aim was to encourage food addicts to beat their addictions with the help of a psychologist and nutritionist. It wasn't easy. He had to eat a fish dish, while his brother sat in front of him enjoying... a pizza! However, Zack met the challenge and has never eaten pizza again.
Seventeen-year-old Stacy Irvine's friends visit her and discover that she has been rewarded thousands of free toys from fast food restaurants as a regular customer. Stacy's mother often gave her two-year-old girl a portion of fried chicken in a McDonald's restaurant. [I] Since then, Stacy has refused to eat anything else except for pieces of fried chicken, and as a result, her diet has created serious health. She has been warned that if she doesn't change her diet, she will die. [II] Stacy once collapsed due to lack of vitamins and nutrients and needed to be hospitalised. [III] She insisted that Stacy adopt a healthier lifestyle. However, worryingly, Stacy's mother said that while Stacy was beginning to understand the seriousness of her situation, she couldn't eat anything else but chicken nuggets. [IV]
Twenty-year-old Hanna Little was keen on chips. The only thing that Hanna consumed for fifteen years was one plate of chips after another. Not surprisingly, a diet that contained few nutrients and an excess of fat and carbohydrates could only have negative consequences. And it did because not only did Hanna develop health problems, but she also had to leave her job after collapsing at work. At five, Hanna became addicted to chips and refused to eat fruits and vegetables despite her mother's efforts. Hanna says that she was terrified of tasting the flavour of different types of food and she would feel anxious just at the idea of doing it. Parties, picnics and barbecues with friends and family used to be a nightmare. Furthermore, Hanna was soon seen as 'odd' by her friends' parents.
It wasn't until the age of sixteen that Hanna realised she had Selective Eating Disorder (SED). Despite this new knowledge, no solution was found. It wasn't until she lost her job before she started eating normally. Hanna sought therapy from psychologist Felix Economakis, who used hypnosis, a treatment that none of the doctors that she had seen before had mentioned, to get her to eat fruit after one one-hour session, and since then she has been willing to eat anything.... including chips!
(Adapted from Friends Global)
The phrase addicted to in paragraph 1 could be best replaced by _____.
Vai trò của ngân sách nhà nước thể hiện như thế nào trong những trường hợp sau: Chính phủ họp bàn xây dựng lộ trình tăng lương cho cán bộ công chức, viên chức?
According to the passage, which of the following is true about the relation between family and society?
Đâu là câu lệnh gán trong Python?
Giá trị của biểu thức Python sau sẽ bằng?
4 + 15 / 5
Phương trình \({\log _3}\left( {{x^2} - 3x - 5} \right) = {\log _3}x\) có bao nhiêu nghiệm?
Ảnh hưởng tích cực của đô thị hoá là gì?
Trong các dãy số sau, dãy số nào là cấp số cộng?
Máy dệt cải tiến với con thoi chuyển động bằng lò xo được phát minh vào năm
Nội dung nào dưới đây không phải chức năng quản lí nhà nước về kinh tế?
Bất phương trình nào sau đây là bất phương trình bậc nhất hai ẩn dạng ax + by + c < 0 ?
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