Tìm kiếm
Whyyyyyyreeeeeeee
1 năm trước

Khi kéo một hộp gỗ trượt trên mặt bàn, giữa hộp gỗ và mặt bàn đã xuất hiện lực ma sát nào? A.Lực ma sát trượt B. Lực ma sát lăn C.Lực ma sát nghỉ D.Không có lực ma sát

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Trong Pham
1 năm trước

Đáp án:

  A. Lực ma sát trượt

Giải thích các bước giải: 

$-$ Lực ma sát trượt sinh ra khi một vật trượt trên bề mặt của vật khác

 $-$ Khi kéo một hộp gỗ trượt trên mặt bàn, giữa hộp gỗ và mặt bàn đã xuất hiện lực ma sát trượt. Vì mặt bàn đã bị ma sát trượt giữa hộp gỗ di chuyển và gọi đúng là trượt trên mặt bàn

$⇒$  Chọn đáp án A . Lực ma sát trượt

Thuc Quan Nek
1 năm trước

Khi kéo một hộp gỗ trượt trên mặt bàn, giữa hộp gỗ và mặt bàn đã xuất hiện lực ma sát trượt

CHÚC BẠN HỌC TỐT, XIN CTLHN Ạ

 

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VI. Complete the second sentence so that it has the same meaning to the first one. 1. I think you should use energy efficient light bulbs. If I_________________________________________________________________ 2. He produced a great idea for our environmental project. He came_____________________________________________________________ 3. Because she was absent from the meeting, she didn’t know the resolution. Because of___________________________________________________________ 4. I won’t take part in the volunteer program because I don’t have enough free time. If I_________________________________________________________________ 5. We need to reduce our plastic waste, otherwise we’ll threaten our own existence, If we________________________________________________________________ 6. Due to the hurricane last night, I was without electric power. Since there___________________________________________________________ 7. People dumped toxic waste Products into the rivers or landfill sites. Toxic waste products___________________________________________________ 8. Air pollution deaths will double by 2050 if nations don’t act. Unless_______________________________________________________________ 9. As the world’s temperatures rise, the Arctic keeps losing its ice. Due to_______________________________________________________________ 10. I live by the sea, so I’m really worried about global warming. If I__________________________________________________________________

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V. Complete the sentences with the correct form of the verbs in brackets. 1. If we________ (not recycle) paper now, we’ll need to cut down more trees in the future. 2. If the local people________ (have) fresh water, they wouldn’t have to use polluted water. 3. What________ (happen) if radioactive material was not handled properly? 4. If we recycle more household waste, there________ (be) less damage to the environment. 5. If we________ (not understand) environmental problems, we would not be able to do anything about them. 6. If the polar ice-caps melted completely, Sea levels worldwide________ (rise) about 60 metres. 7. The amount of plastic in the ocean________ (increase) if we________ (not take) action now. 8. These fish________ (not die) if the factory ________ (not dump) its toxic waste into the river. 9. There ________ (not be) enough oxygen if we ________ (not protect) the rainforests. 10. If I ________ (be) the President, I ________ (ban) billboards in cities in order to reduce visual pollution.

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IV. Choose the best answer to complete the sentences. 1. The river water is severely polluted, mostly________ the dumping of raw sewage. A. due to B. lead to C. because D. so 2. Sudden changes in water temperature can ________ mass killings of fish, plants, or amphibians. A. come up B. result in C. dump into D. thank to 3. Water pollution________ the death of all forms of life in the water bodies. A. occurs B. results of C. creates D. leads to 4. ________ plastic takes so long to break down, it pollutes the land and ocean. A. Because B. Due to C. Even if D. Although 5. Many flights were cancelled ________ the smoke from forest fires. A. so B. because C. because of D. result in 6. ________the garbage dump smells terrible, no one lives around there. A. Because of B. As C. As a result of D. Even though 7. ________the grain consumption is rising, forests will be cut to provide more room for planting crops. A. since B. Although C. unless D. Due to 8. Grace didn’t love nature, ________ she wasn’t happy when her group went camping in a jungle. A. but B. and C. because D. so 9. Thousands of fish were killed ________ a discharge of poisonous Chemicals from a nearby factory. A. because B. lead to C. result in D. as a result of 10. ________the fog, there were no take-oils from the airport yesterday. A. Since B. Because C. Owing to D. Thanks to

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III. Underline the right option. The planet’s water reserves are constantly polluted by waste from agriculture, industries, and (1) sewage / sewers / sewing. Since water is always circulating through the environment, it transports the (2) pollution / polluted / pollutants it contains from one area to the next. A pesticide that is (3) sprayed / spread / crowded on a field, for example, seeps into the groundwater, finds its way to a stream, and finally (4) ends up / gives up / comes up in the ocean. These toxic substances harm (5) poisonous / aquatic / dead plants and animals, and also infect the food Chain, causing certain plant and animal species to become (6) extinct / extinction / extincted. They can also (7) effect / defect / affect humans who eat fish. Even though (8) dumping / collecting / clearing garbage in the ocean is strictly forbidden, many countries release their (9) treated / untreated / treatment sewer waste and dispose of their garbage into the water. In addition to this, more than 6 million tons of oil are accidentally (10) spilled / littered / floated into the ocean every year.

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Please turn off ___ lights when you leave ___ room.

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Choose the best answer.

I like _____ colorful costumes of ____ ethnic minority people in Vietnam.

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