Dao động của một chất điểm có khối lượng 100 g là tổng hợp của hai dao động điều hòa cùng phương, có phương trình li độ lần lượt là x1=5cos10t và x2=10cos(10t+π) (x1 và x2 tính bằng cm, t tính bằng s). Mốc thế năng ở vị trí cân bằng. Cơ năng của chất điểm bằng
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- $m = 100g = 0.1 kg$
- $\omega = 10 rad/s$
- $x_1 = 5cos(10t)$
- $x_2 = 10cos(10t + \pi) = -10cos(10t)$
Cơ năng của chất điểm:
$E = \frac{1}{2} m \omega^2 A^2 = \frac{1}{2} * 0.1 * 10^2 * (0.05)^2 = 0.0125 J = 12,5 mJ$
Do $x_2$ ngược pha với $x_1$ nên biên độ tổng hợp là $|A_1-A_2|=|5-10|=5$. Vậy $A=5$ cm. Cơ năng: $E = \frac{1}{2}m\omega^2A^2=\frac{1}{2}.0,1.10^2.(0,05)^2 = 0,0125 J = 12,5 mJ$ .
Đổi $x_2=10cos(10t+\pi)=-10cos(10t)$.
Do đó $x=x_1+x_2=-5cos(10t)$. Vậy $A=5$ cm
$E = \frac{1}{2}m\omega^2A^2=\frac{1}{2} . 0,1. 10^2 . (0,05)^2=0,0125J=12,5mJ$
$x = x_1 + x_2 = 5cos(10t) - 10cos(10t) = -5cos(10t)$
$A = |-5| = 5cm = 0.05m$
$E = \frac{1}{2} m \omega^2 A^2 = \frac{1}{2} * 0.1 * 10^2 * (0.05)^2 = 0.0125 J = 12.5 mJ$
Tổng hợp dao động: $A = |5 - 10| = 5 (cm)$
Cơ năng: $E = \frac{1}{2} m w^2 A^2 = \frac{1}{2} * 0.1 * 10^2 * (0.05)^2 = 0.0125J = 12.5 mJ$
Câu hỏi liên quan
Read the following passage about the The Importance of Social Media in Modern Society 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.
In the 21st century, social media has become a crucial element of everyday life[I]. Platforms such as Facebook, Twitter, Instagram, and TikTok link individuals around the world, [IV]. Although some may critique social media for promoting negativity, it is important to acknowledge its numerous positive effects on society[III]. This essay will delve into the importance of social media, its influence on shaping public perception, and the challenges it poses.[II]
One of the primary benefits of social media is its ability to foster communication and connection. People can maintain relationships with friends and family, regardless of geographical barriers. This aspect is particularly vital for those who live far away from loved ones. For example, a student studying abroad can easily share their experiences with family through posts, photos, and video calls. Furthermore, social media enables individuals to connect with like-minded people and build communities around shared interests or causes. Activist groups, for instance, often use social media platforms to rally support for important issues, raising awareness and mobilizing action more efficiently than traditional methods.
Moreover, social media serves as a powerful tool for information dissemination. News spreads rapidly through these platforms, allowing individuals to stay informed about current events. During emergencies, such as natural disasters, social media can provide crucial information in real time, helping people stay safe and informed. However, this rapid dissemination of information also raises concerns about the accuracy and reliability of the content being shared. Misinformation can spread just as quickly as legitimate news, leading to confusion and mistrust.
Despite the challenges posed by misinformation, social media plays a significant role in shaping public opinion. People often turn to these platforms to voice their opinions and engage in discussions on various topics. For instance, political debates and social movements frequently gain traction through social media, allowing individuals to express their views and influence others. This democratization of discourse can empower marginalized voices and facilitate social change. However, it is crucial to approach online discussions critically, as echo chambers can form, reinforcing existing beliefs rather than encouraging open dialogue.
In conclusion, while social media presents challenges such as misinformation and polarized discussions, its positive contributions to communication, information dissemination, and social activism cannot be overlooked. As society continues to evolve, it is essential to harness the potential of social media while being mindful of its pitfalls. By promoting responsible use and critical thinking, we can maximize the benefits of social media and foster a more connected and informed society.
The word “democratization” in paragraph 4 is OPPOSITE in meaning to_______.
Read the following passage about Champions of the Overlooked 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 18 to 22.
In every community, there are special people who help those who cannot speak for themselves. These champions work tirelessly to bring attention to forgotten issues and overlooked individuals. They believe that every person deserves dignity and respect, regardless of their circumstances. Animal rights activists are dedicated individuals (18)_________. Many homeless people are ignored by society, but they deserve our attention and support. Children with disabilities often face barriers to education; however, dedicated teachers create inclusive classrooms for all students. The elderly share their wisdom and experience while needing our care and respect. If more resources were provided, (19)_________. Environmental defenders protect natural habitats and speak for future generations who will inherit our planet. They monitor pollution levels, plant trees, and educate communities about sustainability. These champions often work without recognition, (20)_________.
Volunteers at animal shelters provide food, medical care, and love to abandoned pets. (21)_________. Many of these helpers also advocate for stronger animal protection laws and better education about responsible pet ownership. Their dedication shows us how much impact one person can have on many lives. (22)_________. Their work reminds us that true humanity means caring for all living beings, especially those who cannot advocate for themselves. By supporting these champions, we too can help build a more compassionate and inclusive society where everyone is valued and heard.
Chương trình Công nghệ 10 giới thiệu mấy thành tựu của ứng dụng công nghệ cao trong trồng trọt trên thế giới?Khi cây chịu tác động của hạn hán, có thể hình thành phản ứng chống chịu nào sau đây?
Đọc đoạn tư liệu sau đây:
Một nhà du hành người Ai Cập đã viết: Sông Nin của Ai Cập hơn hẳn các dòng sông khác trên thế giới về vị ngọt, độ dài và cả sự hữu ích của nó. Không dòng sông nào khác trên thế giới có thể quy tụ bên bờ của nó nhiều thành phố và làng mạc đến vậy"... Người Ai Cập gọi vùng đất phì nhiêu của họ là "Vùng đất đen" vì màu của phù xa và cây trồng rậm rạp trên đó. Ngoài dải đất dài và hẹp của những cánh đồng màu mỡ ấy là sa mạc (được gọi là "Vùng đất đỏ").
(Theo Uy-li-am G.Đu-khơ, Giắc-xơn G.Spi-en-vô-ghen,
Lịch sử thế giới (bản tiếng Anh) NXB Oát-uốt, 2010, tr.16)Nhận định nào về quang hợp là đúng?
Read the following advertisement and mark the letter A, B, C, or D to indicate the option that best fits each of the numbered blanks from 1 to 6.
Discover the Future of Tech with SmartGadgets
Ø Experience (1) ______ like never before with our smartphones that redefine connectivity.
Ø Our (2) ______ will enhance your daily life and keep you ahead of the curve.
Ø Join thousands of customers (3) ______ with their purchases and enjoy unparalleled performance.
Ø Show the features (4) ______ your customers that truly set you apart from the competition.
Ø Don’t miss out on this (5) ______ -in-a-lifetime opportunity to upgrade your tech.
Ø Start (6) ______ the benefits of advanced technology today, or wait for the future to catch up!
v With SmartGadgets, you’re not just purchasing a product; you’re investing in a lifestyle. Explore our collection now!
Ø Show the features (4) ______ your customers that truly set you apart from the competition.
The increase in earth's temperature can cause heat-related illnesses.
Dao động điều hòa đổi chiều khi
Một trong những biểu hiện của bài học về phát huy tinh thần yêu nước của các cuộc kháng chiến bảo vệ Tổ quốc từ năm 1945 đến nay là
Pháp luật là quy tắc xử sự chung, được áp dụng đối với tất cả mọi người là thể hiện đặc trưng nào dưới đây của pháp luật?
Read the following passage about wildlife conservation 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 23 to 30.
Wildlife conservation is a crucial endeavor that aims to protect animal species and their habitats. This effort is essential for maintaining biodiversity and ensuring the health of our ecosystems. Human activities such as deforestation, pollution, and climate change are some of the primary threats to wildlife. Conservation initiatives strive to mitigate these impacts through various strategies.
One significant aspect of wildlife conservation is the establishment of protected areas. National parks, wildlife reserves, and marine protected areas are created to provide safe havens for endangered species. These areas not only protect wildlife but also offer opportunities for scientific research and eco-tourism, which can benefit local economies.
Another important approach is the reintroduction of species into their natural habitats. This method has been successful in bringing several species back from the brink of extinction. Conservationists carefully monitor and support these reintroduced populations to ensure their survival.
Education and awareness campaigns play a pivotal role in wildlife conservation as well. By educating the public about the importance of biodiversity and the threats facing wildlife, these campaigns foster a sense of responsibility and encourage community involvement in conservation efforts.
Technological advancements are also aiding conservation efforts. Innovations such as satellite tracking, DNA analysis, and drone surveillance help researchers gather critical data and monitor wildlife populations more effectively. These tools enable more informed decision-making and efficient conservation strategies.
The word ‘their’ in paragraph 3 refers to ______.
Cho hai tập hợp A={1;2;3;7}, B={2;4;6;7;8}. Mệnh đề nào sau đây đúng?
Màng sinh chất ở tế bào nhân thực không có chức năng nào sau đây?
Phát biểu nào dưới đây là sai?
Sự khác nhau của hai nhóm vi khuẩn Gram âm và Gram dương là ở đặc điểm nào?
Rewrite the sentence and keep it the same meaning as the first one. No more than FIVE words in the blank.
We will recycle plastic bottles to keep the ocean clean.
Một sợi dây căng ngang đang có sóng dừng. Sóng truyền trên dây có bước sóng λ. Khoảng cách giữa hai nút liên tiếp là
Khi hai vật có nhiệt độ khác nhau tiếp xúc với nhau, nhiệt năng sẽ
- Đồ thị hàm số \(y = \frac{{ - {x^2} + 4x - 3}}{{x + 2}}\) có đường tiệm cận xiên là
