GIÚP MÌNH NHE!!!! mình cần gấp-.- một vật được thả không vận tốc đầu từ đỉnh của một mặt phẳng nghiêng cao 20m, góc nghiêng 30 độ so với phương ngang, biết vật có khối lượng 100g, lấy g=10m/s2 1. trong trưởng hợp bỏ qua ma sát hãy tìm : a. tìm cơ năng của vật b. tìm vận tốc tại giữa dốc c, tìm vận tốc tại chân dốc 2, trường hợp có ma sát, cơ năng tại chân mặt phẳng nghiêng giảm 20% so với khi không ma sát. hãy tìm hệ số ma sát.

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III. Finish the second sentence so that it has a similar meaning to the first one, beginning with the given words. 1. The teacher was too tired to teach us how to swim. The teacher was not____________________________________________________________ 2. The mother made the little girl go to bed in time. The little girl_________________________________________________________________ 3. She can’t go to school today because she is ill. If she_______________________________________________________________________ 4. My sister began to learn English when she was six years old. My sister has_________________________________________________________________ 5. The car was so expensive that my dad didn’t buy it. The car was too________________________________________ IV. Combine two sentences into a new one using the given words in brackets. Do not change the given words in any ways. 1. She stayed at home. She did not go to see him. (instead of) ____________________________________________________________________________ 2. The exercise was very long. Jimmy couldn’t do it in thirty minutes. (too) ____________________________________________________________________________ 3. He tried hard. He couldn’t set up a new world record. (although) ____________________________________________________________________________ 4. He went on holiday. I went on holiday. (both....and) ____________________________________________________________________________ 5. Mary’s room is dirty. It is messy too. (not only.....but) p/s: mk cần gấp ạ. thanks ạ