Giúp mình giải bài tập 2 được không
Một vật nhỏ trượt không vận tốc đầu từ một đỉnh dốc A cao 5met. Khi xuống dưới chân dốc B vận tốc của vật là 6met. Cơ năng của vật có bảo toàn không? Giải thích.
VI. : Choose one sentence that has the same meaning as the roof 31.Study hard or you will fail the exam. A. If you didn’t study hard, you wouldn’t fail the exam. B. If you study harder, you won’t pass the exam. C. If you don’t study hard, you will fail the exam. D. If you don’t study hard, you will pass the exam. 32.“ I’m going on the Internet now.” Minh said A. Minh said he is going on the Internet now. B. Minh said I am going on the Internet now. C. Minh said us he was going in the Internet then. D. Minh told us he was going on the Internet then. 33. You can’t visit the United States unless you get a visa. A. You can’t visit the United States since you don’t get a visa. B. If you don’t get a visa, you cannot visit the United States. C. Although you get a visa, you can’t visit the United States. D. You can visit the United States even if you don’t get a visa. 34. I’ll be happy to give you a lift. A. Would you mind giving me a lift? B. Giving me a lift will make you happy. C. I’ll be happy if you give me a lift. D. I don’t mind giving you a lift. 35. Food can’t be sold on the sidewalk. A. They can’t sold food on the sidewalk. B. They can’t be sold food on the sidewalk. C. They can’t sell food on the sidewalk. D. They couldn’t sell food on the sidewalk. 36. It’s a pity I can’t play the guitar well. A. I wish I could play the guitar well. B. I wish I couldn’t play the guitar well. C. I wish I can’t play the guitar well. D. I wish I can play the guitar well. 37. The children are fond of reading picture books. A. The children like reading picture books. B. The children are interested in reading picture books. C. The children are keen on reading picture books. D. All are correct. 38. The last time I spoke to her was five years ago. A. I haven’t spoken to her for five years. B. I have spoken to her for five years. C. I saw her last five years ago. D. I saw last her five years ago. 39. Why don’t we recycle bottles and cans? A. We must recycle bottles and cans, mustn’t we? B. What do we recycle bottles and cans for? C. Shall we recycle bottles and cans? D. How can we recycle bottles and cans? 40. I’m very pleased that we will meet again soon. A. I think we should meet again soon. B. I’m looking forward to meeting you again soon. C. Please don’t come and meet us again. D. I’ve been looking for you for a long time.
Quần sát hình 41.1,42.1 SGK em hãy cho biết khí hậu ở Trung Và Năm Mĩ có sự phân hoá theo chiều A . Từ bắc xuống nam B . Từ tây sang đông C từ thấp lên cao D cả ba đáp án trên
V. Read the passage then choose the best answers that fit the questions below. It is estimated that about 200 million people who use the Internet computer network around the world. The Internet allows people to work at home instead of traveling to work. The Internet allows businesses to communicate with customers and workers in any part of the world for the cost of a local telephone call. Email allows users to send documents, pictures and other data from one part of the world to another in at least 5 minutes. People can use the Internet to do shopping. This save a lot of time. It is possible to use the Internet for education – students may connect with their teachers from home to send or receive emails or talk their problems through ’on-line’ rather than attend a class. 26. How the Internet help people with their work? A. They must stay at home to work. B. They do not have to work at the office. C. They can stay at home to work. D. They have to travel to work. 27. How much does it cost for a businessman to communicate with customers. A. It is very cheap. B. It is quite expensive. C. It costs a lot of money. D. It costs no money. 28. According to the passage, what can users do when they want to sends some photos to a friend? A. They have to go to the post office. B. They can send them by emailing. C. They can send them by bus. D. They can only send documents. 29. How long does it take to do the shopping on the Internet? A. It takes a lot of time. B. It takes nearly no time. C. It takes less time. D. It takes more time. 30. What can students do when they stay home for COVID-19? A. It is impossible for them to study. B. It is possible to contact their teachers. C. They can play games with their teachers. D. They can join in online lessons with others.
Cho đoạn thẳng AB=5cm,CD=2dm tính tỉ số của hai đoạn thẳng AB và CD
Viết một đoạn văn tiếng anh về môn thể thao mà bạn yêu thích Bạn nào viết hay mik vote 5 sao
1) Dùng một cần trục nâng một kiện hàng có khối lượng 1,2 tấn lên độ cao 9m theo phương thẳng đứng với vận tốc 15 cm/s . hãy tính công và công suất của cần trục(3 điểm) 2) Kích thước của 1 phân tử hidro vào khoảng 0,00000023mm. Hãy tính độ dài 1 chuỗi gồm 1 triệu phân tử này xếp nối tiếp nhau. (1 điểm) 3) Bỏ vài hạt thuốc tím vào cốc nước . Mặc dù không khuấy lên nhưng sau một thời gian ngắn, toàn bộ nước trong cốc có màu tím. Hãy giải thích tại sao?(1 điểm) Nếu tăng nhiệt độ của cốc nước thì hiện tượng trên xảy ra nhanh hay chậm hơn. Tại sao?
IV.Read the text below and mark the letter A, B, C or D on your answer sheet to decide which answer best fits each space from 1 to 5. Most people think of computers as very modern inventions, products of our new technological age. But actually the idea for a computer had been worked out over two centuries ago by a man (1)_____ Charles Babbage. Babbage was born in 1791 and grew up to be a brilliant mathematician. He drew up plans for several calculating machines which he called "engines". But despite the fact that he (2)_____ building some of these, he never finished any of them. Over the years people have argued (3) _____ his machines would ever work. Recently, however, the Science Museum in London has finished building (4) _____ engine based on one of Babbage's designs. (5) _____ has taken six years to complete and more than four thousand parts have been specially made. Whether it works or not, the machine will be on show at a special exhibition in the Science Museum to remind people of Babbage's work. 21. A. written B. called C. recognized D. known 22. A. started B. wanted C. made D. missed 23. A. until B. though C. whether D. why 24. A. that B. the C. some D. an 25. A. He B. They C. One D. It
Anh chị giúp em với ạ em cần gấp nộp thầy
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