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2 năm trước
Người ta kéo một vật có khối lượng 8kg lên cao 4m bằng mặt phẳng nghiêng dài 8m với lực kéo 50N a, Tính công của lực thực hiện được b, Tính lực ma sát khi kéo vật lên cao bằng mặt phẳng nghiêng
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The Eiffel Tower The Eiffel Tower is located in Paris, France. It was constructed between 1887 and 1889 to be the entranceway to the 1889 World's Fair and to celebrate the 100th anniversary of the French Revolution. The Tower was opened to visitors on May 6,1889. Gustave Eiffel's design was chosen from among 107 that were submitted to the World's Fair design competition. However, many Parisians, especially artists, did not like his design and protested the tower's construction. They thought it would be an eyesore, but once it was built, most Parisians soon loved the tower. The tower is made of iron and weights over 10,000 tons. It is 324 meters tall, including antenna at its top, and has a staircase with 1,665 steps. There are also elevators to take visitors to the top platform where there is a panoramic view of Paris. The original elevators, now computerized, are still in use. Over 60 tons of paint are applied to the tower every seven years to keep it from rusting. The Eiffel Tower has become a symbol of Paris. It is the most recognized monument in Europe, and many people think it is an architectural masterpiece. Over 250 million people have visited it since May of 1889. A. Decide if the statements are true (T) of false (F). 1. The Eiffel Tower was originally built to be a watchtower. 2. The Eiffel Tower was opened to the public on May 6,1889. 3. Some artists at the time thought the tower was ugly. 4. The original elevators in the tower have all been replaced. 5. The tower is repainted every seven years. 6. The Eiffel Tower is the most recognized structure on the planet. B.Answer the questions: 1 Where is the Eiffel Tower 2How long was the tower constructed 3Who designed the Eiffel Tower 4Why does the tower have to be painted frequently 5How many people have visited the Eiffel Tower since its opening

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