题目

如图所示,摩托车做腾跃特技表演,以v0=10 m/s的初速度冲上顶部水平高台,然后从高台水平飞出,若摩托车冲向高台的过程中始终以恒定功率行驶,所经历的时间为9 s,人和车的总质量为180 kg,台高h=5 m,车越过高台后,飞出的水平距离s=10m,试求:(1)摩托车刚越过高台时的水平速度v为多大?(2)摩托车发动机的额定功率P至少为多少?(不计任何阻力)Many Chinese students find it difficult English， but not Chinese， because Chinese is own language. Actually， Chinese is to learn than English.Still some foreign students can speak Chinese so that if you didn’t see them， you would take them for Chinese. What makes them ?“ For me， conversation is the most helpful. I use every chance to speak Chinese. If you only listen to what others ， you’ll improve your listening ability， but if you talk as much as ， you’ll find you can express yourself much better，” says Ulrike Nootz， a German girl now studying Chinese at Shanghai International Studies University.Though the Chinese language is difficult， she can learn it well. She thinks that to learn a language one must try to know something about the history of the country. Though Chinese is different from English， the experience of success can be . Conversation， in English learning， very important.1.A. to learn B. learning C. learn2.A. we B. their C. us3.A. very more difficult B. much difficultC. much more difficult4.A. well B. good C. better5.A. success B. succeed C. successfully6.A. in B. by C. with7.A. say B. talk C. speak8.A. can B. possible C. may9.A. the same B. same C. the different10.A. may be B. maybe C. may