Một hòn sỏi được ném thẳng đứng với động lượng P từ mặt đất hãy tìm độ biến thiên động lượng của hòn sỏi bỏ qua sức cản.

Exercise 4: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. FIRST TIME IN THE AIR When John Mills was going to fly in an airplane for the firsttime, he was frightened. He did not like the idea of being thousands of feet up in the air. "I also didn't like the fact that I wouldn't be in control," says John."I'm a terrible passenger in the car. When somebody else is driving, I tell them what to so. It drives ever ybody crazy. "However John coul dn't avoid flyin g any longer. It was the only way he could visit his grandchildren in Canada. "I had made up my mind that I was going to do it, I couldn' t let my son, his wife and their three children travel all the way here to visit me. It would be so expensive for them and I know Tom's businessisn't doing so well at the moment - it would also be tiring for the children - it's a nine-hour flight!" he says.To get ready for the flight John did lots of reading about airplanes. When he booked his seat, he was told that he would be flying on a Boeing 747, which is better known as a jumbo jet. "I needed to know as much as possible before getting in that plane. I suppose it was a way of making myself feel better. The Boeing 747 is the largest passenger aircraft in the world at the moment.The first one flew on February 9th 1969 in the USA. I t can carry up to 524 passengers and 3.400 pieces of luggage. The fuel for airplanes is kept in the wings and the 747' s wings are so big that they can carry enough fuel for an average car to be able to travel 16,000 kilometers a year for 70 years. Isn' t that unbelievable? Even though I had discovered all this very interesting information about the jumbo, when I saw it for the first time, just before I was going to travel to Canada, I still couldn't believe that something so enormous was going to get up in the air and fl y. I was even more impressed when I saw how big it was inside with hundreds of people!" The biggest surprise of all for John was the flight itself. "The take-off itself was much smoother than I expected although I was still quite scared until we were in the air. In the end, I managed to relax, enjoy the food and watch one of the movies and the view from the window was spectacular. I even managed to sleep for a while! "Of course, " continues John, "the best reward of all was when I arrived i n Canada and saw my son and his famil y, parti cul arl y my beautiful gr andchildren. Suddenl y, I felt so sill y about all the years when I couldn't even think of getting on a plane. I had let my fear of living stop me from seeing the people I love most in the world. I can visit my son and famil y as often as I like now!" Question 24: Why did John Mills fly in an airplane? A. He wanted to go on holiday B. He wanted to try it. C. He wanted to see his family D. He had to travel on business. Question 25: Why did John read about airplane? A. He wanted to know how they work. B. I t was his hobby. C. I t made him fee l safer . D. He had found a book on them. Question 26: What does the word "which" in the paragraph refer to? A. reading about airplanes B. booking his seat C. f ly ing on a Boe ing 747 D. a Boeing 747 Question 27: What happened when he saw the jumbo jet for the first time? A. He felt much safer . B. He liked the shape of it. C. He couldn't believe how big it was. D. He thought the wings were ver y small. Question 28: How did John feel when the airpl ane was taking off? A. excited B. happy C. s a d D. frightened Question 29: What surprised John most about the fli ght? A. that he liked the food. B. that he was able to sleep C. that there was a movie being shown D. that the view was good Question 30: How did John feel about his fears in the end? A. He thought he had wasted time being afraid. B. He realized it was okay to be afraid. C. He hoped his grandchildren weren't afraid of flyi ng. D. He realized that being afraid kept him safe.

1. There .....( be) less trash in the street since the "Keep our neighborhood clean" campaign was launched Help me !!

Trình bày suy nghĩ của em về việc "bảo vệ sức khỏe cộng đồng" trước đại dịch cho virut Corona gây ra!!!!

Câu 31Đ – S Cho tia Ot nằm giữa hai tia Ox và Oy, ta có Phát biểu Đ S a) Hai góc xOt và tOz phụ nhau b) Hai góc xOt và tOz bù nhau c) Hai góc xOt và tOz kề nhau d) Hai góc xOt và tOz kề bù Câu 32 Cho tia Oy nằm giữa hai tia Ox và Oz. Biết xOy = 50o. Để góc xOz là góc tù thì góc yOz phải có số đo A. yOz > 40o B.40o<yOz<130o C. 40o≤yOz<130o D. 40o<yOz≤130o Câu 33 Cho tia Oy nằm giữa hai tia Ox và Oz. Biết góc xOy có số đo là 50o, góc xOz có số đo là 120o A. Góc yOz là góc nhọn B. Góc yOz là góc tù C. Góc yOz là góc bẹt D. Góc yOz là góc vuông Câu 34 Chọn kết quả tương ứng của cột B cho các phép tính ở cột A Cho tia Ox, hai góc xOy và xOz trên cùng một nửa mặt phẳng có bờ chứa tia Ox sao cho góc xOy có số đo mo và góc xOz có số đo no Cột A cột a) Nếu m=20o và n=30o thì 1) Tia Ox nằm giữa hai tia Oy, Oz b) Nếu m=45o và n=30o thì 2) Tia Oy nằm giữa hai tia Ox, Oz 3) Tia Oz nằm giữa hai tia Oy, Ox

Em hãy nêu 3 dẫn chứng phù hợp cho đề văn sau: Chứng minh tính đúng đắn của câu tục ngữ “Có công mài sắt, có ngày nên kim”

BÀI TẬP ĐỌC HIỂU TIẾNG ANH Exercise 1: 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 hundreds of years, giving flowers have been a social means of communication. In the United States , flowers are often given during rites(nghi thức) of passage, for commemorating special occasions(dịp) or as a heartfelt(chân thành) gift between loved ones and friends. Flower gifting also occurs(hầu hết) in most countries around the world. However, the meanings and traditions often vary(khác nhau).While students tradition ally gave thei r favori t e teacher an apple in past years , in China, teachers are given flowers. Peonies are b far the flower most often given in China. They are also quite popularly used for weddings . Stran gely, potted plants are not consid er ed a pleas ant gift among Asian cultures. The people believe that like a plant confined by a pot, the gift s ymbolizes a bi ndi ng or restri cti on.In Russia, in lieu of givi ng bi rthday pres ents, the guest of honor receives a single flower or an unwrapped bouquet . Flo ral arrangements or basket s are not giv en. Russi ans cel ebrat e a holiday known as Woman's Day. Traditi onal gifts include red roses, hyacinths or tulips. When there is a funeral or other occasion where someone wishes to express s ympath y,carnations, lilies or roses are given in circular configurations, which signify the transition of birth, life and death to rebirt h. In thi sinstance, the color of choice i s commonly yellow. For joyo s o ccasions , arrangements and bouquets generall y contain an odd number of fl owers. In the times of ancient Rome, brides carried flowers to scare away evil spirits and encourage fertility. The Dutch believed that flowers were food for the soul. When invited to someone's white lilies, which are usuall y seen at funerals. Unlike the United States, red roses are a symbol of love. Flowers are generall y gifted in odd numbered increment s regardless of the occasion. However, the Brits also have supersti tions regarding the number 13, so the number is avoided. In the southern region of the continent, flowers are traditionall y given during Christmas. Egyptians are much more conservative and restrict flower gifting to funerals and weddings. While certain flowers may have significant meanings for some, flowers in Las Vegas and across the United States flowers are an accepted gift for any reason desired. Question 16: What does the topic mainly discuss? A. The fascinating tradition of giving flowers. B. The different meanings of flowers in different cultures. C. The comparison of giving flowers between Asian and European cultures. D. The kinds of flowers people often give each other in different cultures. Question 17: What does the word "They" in paragraph 2 refer to? A. Stude nt s B. Teac her s C. Flowe r s D. Peonies Question 18: Why should not you give a potted plant to an Asian? A. Because the Asian prefer to be given flowers. B. As this gift is often given at weddings in Asia. C. Since this gift is believed to sy mbolize an astriction and limitation in Asia. D. Because Asian students like to give an apple or flowers to others. Question 19: According to the passage, the following flowers are given at Woman's Day in Russia, EXCEPT . A. red roses B. hy ac inths C. tul i ps D. yellow roses Question 20: What could the word "fertility" in paragraph 4 best be replaced by ? A. fec undi ty B. good spirit C. happiness D. loyalty Question 21: The word "superstitions" in paragraph 4 is closest in meaning to A. deep-seated belief B. unfounded belief C. religious belief D. traditional belief Question 22: In which country should not people bring white lilies to other houses? A. China B. Russia C. Great Britain D. United States Question23: It can be inferred from the passage that A. People can give flowers to the American in any occasion. B. Egyptians are rather comfortable when receiving flowers at funerals and weddings. C. Flowers given in Britain are in even numbers in any case. D. At the funerals in any cultures, flowers are gifted in circular configurations.

anh ( chị ) có suy nghĩ gì về câu nói :" bàn tay tặng hoa hồng bao giờ cũng phẳng phất hương thơm "

Cho tam giác ABC. Trên AB lấy điểm D sao cho AD = 2BD , trên AC lấy điểm E sao cho EC = 1/2AE. So sánh diện tích tam giác ADE và ABC. ( Nhớ vẽ hình làm nhanh hộ mình nha bây giờ mình phải nộp rồi mk cảm ơn nhiều )

X. Read the passage carefully and do the tasks. There are many kinds of pollution. Air, water, and land can be polluted. Some pollution is caused by nature, such as foods, forest fires, and volcanoes. People are the major Cause of pollution. We pollute the air with our cars, homes, and factories. Smoke from factories and car exhaust makes the air looks gray and smoggy. Some people cannot go outside when the air is very bad! We pollute the water by dumping garbage and Chemicals in the water. Plants and animals die because of the pollution in the water. We pollute the soil with Chemicals and garbage. We harm the land by cutting down trees in the forest, especially to build roads and new houses without careful planning and thinking. The only way to save our environment is to think about pollution. How can you stop or limit pollution? How do we protect our environment? Conservation is one way to protect our environment. Conservation is the wise use and protection of our environment. We can control water pollution by not producing as much as waste and by proper disposal of sewage and garbage. We can take care of recreation land by cleaning up, after ourselves and not causing more pollution. Carpooling and public transportation will help reduce air pollution. Recycling is a type of conservation. Recycling is reusing items over again or in a new way. Recycling can help us conserve our natural resources so they will last many more years. A. Find the word in bold in the passage that means: 1. the protection of the natural environment ________ 2. have a bad effect on something ________ 3. a large amount of water covering an, area that usually dry ________ 4. sharing a car ride with other people ________ 5. waste gases that come out of an engine ________ 6. the process of making air, water, soil, etc. dirty ________ 7. get rid of ________ B. Choose the correct answers. 1. According to the passage, pollution________ A. is always caused by humans. B. can only be caused by nature. C. is mainly caused by humans. D. may sometimes cause natural disasters. 2. What kind of pollution may a car cause? A. Air pollution B. Water pollution C. Soil pollution D. Light pollution 3. Which of the followings is not an example of soil pollution? A. Land development B. Waste disposal C. Pesticide or fertilizer use D. Exhaust from traffic 4. How can we help save our environment? A. Stop pollution. B. Dump garbage into the river. C. Drive cars everywhere. D. Cut down trees in the forests. 5. How does recycling help the environment? A. It expands landfills. B. It saves natural resources. C. It increases water pollution. D. It causes air pollution. 6. What can we do to help reduce air pollution? A. Walk or bike B. Carpool to work or school C. Use public transport D. All of the above 7. What is the main idea of this article? A. The air is dirty because of cars and factories. B. The soil gets polluted from littering. C. People cause pollution, but they can also stop or limit it. D. Conservation is the only way to stop environmental pollution.