Dùng tay cọ xát miếng kim loại vào sàn nhà thì thấy miếng kim loại nóng lên. Trong các kết luận sau đây, kết luận nào đúng, kết luận nào sai?
Mặt tiếp xúc giữa miếng kim loại và sàn nhà có ma sát.
Khi cọ xát trong thời gian đủ dài có thể tạo ra lửa.
Ta đã làm thay đổi nội năng của miếng kim loại bằng cách truyền nhiệt.
Nội năng của miếng kim loại giảm.
Hãy suy nghĩ và trả lời câu hỏi trước khi xem đáp án
a) đúng vì khi cọ xát miếng kim loại vào sàn nhà, có lực ma sát tác dụng giữa bề mặt của miếng kim loại và sàn nhà. Lực ma sát này là nguyên nhân gây ra sự tăng nhiệt độ của miếng kim loại.
b) đúng.
Nội năng của miếng kim loại tăng lên do công cơ học được thực hiện bởi lực ma sát, không phải do truyền nhiệt.
Suy ra c) và d) Sai.
Bộ Đề Kiểm Tra Tham Khảo Giữa Học Kì I - Môn Vật lí 12 - Kết Nối Tri Thức được biên soạn và tổng hợp những kiến thức cơ bản đã học nhằm giúp học sinh củng cố kiến thức, đánh giá năng lực, và chuẩn bị tốt hơn cho các kỳ thi quan trọng sắp tới.
Câu hỏi liên quan
Đâu là ý đúng: Theo chức năng, người ta chia mạch điện tử điều khiển làm mấy loại?
Read the following passage about a football player 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.
Cristiano Ronaldo, one of the greatest football players of all time, (18) __________.
Born on February 5, 1985, in Funchal, Madeira, Portugal, he showed exceptional talent from a young age. His journey began at Sporting Lisbon, where he honed his skills before moving to Manchester United in 2003. There, he developed into a formidable player, winning multiple Premier League titles and the coveted UEFA Champions League.
During his time at Manchester United, Ronaldo developed into a world-class player, winning three Premier League titles and the UEFA Champions League. He became well known for his incredible speed and powerful shots (19) __________ . In 2009, he transferred to Real Madrid, where he broke numerous records, including becoming the club’s all-time leading scorer. (20) __________.
Possessing remarkable athleticism and a keen sense of strategy, (21) __________. His training regimen, which includes intense workouts and a strict diet, ensures that he remains at peak performance. This dedication has allowed him to adapt his playing style over the years, maintaining his relevance in an ever-evolving sport. Additionally, Ronaldo’s ability to lead his teammates has earned him respect both on and off the field.
Beyond his football career, Ronaldo is a philanthropist who uses his platform to give back to the community. (22) __________. His influence extends far beyond the pitch, making him a global icon and a role model for aspiring athletes. Ultimately, Cristiano Ronaldo’s legacy is defined not only by his records but also by his commitment to making a positive impact in the world.
Chủ thể trong nền kinh tế thị trường định hướng xã hội chủ nghĩa, Nhà nước có vai trò quản nền kinh tế thông qua thực hiện chức năng quản lí nhà nước về kinh tế được gọi là gì?
Đọc đoạn thơ sau và trả lời câu hỏi:
Đường nở ngực. Những hàng dương liễu nhỏ
Đã lên xanh như tóc tuổi mười lăm.
Xuân ơi Xuân, em mới đến dăm năm
Mà cuộc sống đã tưng bừng ngày hội
Như hôm nay, giữa công trường đỏ bụi
Những đoàn xe vận tải nối nhau đi
Hồng Quảng, Lào Cai, Thái Nguyên, Việt Trì
Tên đất nước reo vui bao tiếng gọi...
(Tố Hữu, Bài ca mùa xuân 1961, dẫn theo thivien.net)
Đoạn thơ trên KHÔNG sử dụng biện pháp nghệ thuật nào?
Tình trạng lạm phát không do những nguyên nhân nào sau đây?
Công nghệ nào sau đây được ứng dụng trong chế biến sản phẩm trồng trọt?
Tính chính xác cao trong lĩnh vực cơ khí:
Phần mềm nào chạy trên Internet mà không đòi hỏi mất phí sử dụng?
Cấu tạo li hợp ma sát gồm mấy phần?
Chọn ý đúng: Ở nước ta nơi có hoạt động giao thông đường sông phát triển nhất là?
Khi nói về cấu tạo của hạt nhân, ý nào không đúng?
Phương trình \(\sqrt {{x^2} + 2x - 3} = 5 - x\) có nghiệm là \(x = \frac{a}{b}\). Khi đó \(a + 2b\) bằng?
Phát biểu nào sau đây là sai?
Người ta vẽ hình chiếu trục đo của đường tròn nằm trên mặt phẳng song song với mặt tọa độ theo mấy bước?
Sự xâm nhập của nước vào tế bào lông hút theo cơ chế nào sau đây?
Cho kí hiệu nguyên tử \({}_8^{17}O\) . Khẳng định nào sau đây sai?
Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions:
For many people who live in cities, parks are an important part of the landscape. They provide a place for people to relax and play sports, as well as a refuge from the often harsh environment of a city. What people often overlook is that parks also provide considerable environmental benefits.
One benefit of parks is that plants absorb carbon dioxide - a key pollutant - and emit oxygen, which humans need to breathe. According to one study, an acre of trees can absorb the same amount of carbon dioxide that a typical car emits in 11,000 miles of driving. Parks also make cities cooler. Scientists have long noted what is called the Urban Heat Island Effect: building materials such as metal, concrete, and asphalt absorb much more of the sun’s heat and release it much more quickly than organic surfaces like trees and grass. Because city landscapes contain so much of these building materials, cities are usually warmer than surrounding rural areas. Parks and other green spaces help to mitigate the Urban Heat Island Effect.
Unfortunately, many cities cannot easily create more parks because most land is already being used for buildings, roads, parking lots, and other essential parts of the urban environment. However, cities could benefit from many of the positive effects of parks by encouraging citizens to create another type of green space: rooftop gardens. While most people would not think of starting a garden on their roof, human beings have been planting gardens on rooftops for thousands of years. Some rooftop gardens are very complex and require complicated engineering, but others are simple container gardens that anyone can create with the investment of a few hundred dollars and a few hours of work.
Rooftop gardens provide many of the same benefits as other urban park and garden spaces, but without taking up the much-needed land. Like parks, rooftop gardens help to replace carbon dioxide in the air with nourishing oxygen. They also help to lessen the Urban Heat Island Effect, which can save people money.
In the summer, rooftop gardens prevent buildings from absorbing heat from the sun, which can significantly reduce cooling bills. In the winter, gardens help hold in the heat that materials like brick and concrete radiate so quickly, leading to savings on heating bills. Rooftop vegetable and herb gardens can also provide fresh food for city dwellers, saving them money and making their diets healthier. Rooftop gardens are not only something everyone can enjoy, they are also a smart environmental investment.
Question 37: Using the information in paragraph 2 as a guide, it can be inferred that ______.
Năm 1945, nhân dân một số nước Đông Nam Á giành được độc lập trong điều kiện khách quan nào sau đây?
Nội dung nào dưới đây cho thấy các dân tộc sinh sống trên đất nước Việt Nam đều bình đẳng về kinh tế?
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 from 23 to 30.
The 22nd Southeast Asian Games were held in Vietnam from December 5th to 13th, 2003. It marked the first time Vietnam hosted such a significant sporting event, yet the Games were a great success. They became a grand festival that impressed sports enthusiasts with their spirit of solidarity, cooperation for peace, and development. The event demonstrated Vietnam's capability to unite the region through sports.
Athletes from 11 participating countries competed in 32 sports, winning a total of 444 gold medals. Teams in table tennis, badminton, karate, volleyball, basketball, and wrestling showcased some of the region’s top competitors. Notably, many records set during the Games were close to international standards. Vietnam emerged victorious, securing 158 gold medals and finishing at the top of the medal standings. Thailand came second with 90 golds, while Indonesia ranked third with 55. Singapore and Vietnam were the only nations with participants honored as the Most Outstanding Athletes in Swimming and Shooting events.
In football, the Vietnamese Women's Football team successfully defended their SEA Games title, a moment of pride for the host nation. In the Men's Football Final, Vietnam faced Thailand but lost, with the Thai team taking home the gold medal. Other sports, such as karate, athletics, bodybuilding, and wushu, saw young and talented Vietnamese athletes delivering exceptional performances and securing numerous gold medals. The strong performance of the athletes reflected Vietnam's growing prowess in the regional sports arena.
Vietnam’s first-place finish was not surprising. To prepare for the 22nd SEA Games, the country implemented an intensive training program for its athletes, involving both domestic and international facilities. Furthermore, the enthusiastic support from the Vietnamese people inspired the athletes to compete in high spirits. This success solidified Vietnam’s reputation as an excellent host for international sporting events. With this achievement, Vietnam has demonstrated its potential to host even larger competitions, such as the Asian Games, in the future.
In which paragraph is the Vietnamese Women's Football team’s performance mentioned?