问题
选择题
| 如图所示，在一根张紧的水平绳上，悬挂有a、b、c、d、e五个单摆，让a摆略偏离平衡位置后无初速释放，在垂直纸面的平面内振动；接着其余各摆也开始振动。下列说法中正确的有（ ） |
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A．各摆的振动周期与a摆相同 B．各摆的振幅大小不同，e摆的振幅最大 C．各摆的振动周期不同，c摆的周期最长 D．各摆均做自由振动 |
答案
答案：A
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| 如图所示，在一根张紧的水平绳上，悬挂有a、b、c、d、e五个单摆，让a摆略偏离平衡位置后无初速释放，在垂直纸面的平面内振动；接着其余各摆也开始振动。下列说法中正确的有（ ） |
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A．各摆的振动周期与a摆相同 B．各摆的振幅大小不同，e摆的振幅最大 C．各摆的振动周期不同，c摆的周期最长 D．各摆均做自由振动 |
答案：A
| 完形填空。 | ||||
| Preparing for tomorrow Six-grade schoolteacher Ms. Shelton believed in readiness. Students remember how she walked in on the first day of class and began writing words of eight-grade on the 1 . They quickly protested that the words were not on their 2 and they couldn't learn them. Their teacher insisted that the students could and would learn these 3 . She said that she would teach them something that should be given. Ms. Shelton 4 by saying that one of the students in the classroom could go on to 5 , maybe even be president someday, and she wanted to prepare them for that day. Ms. Shelton spoke those words many years ago. 6 did she know that someday one of her students Jesse Jackson would take them 7 . She believed that if they were well prepared, they could 8 high goals. Ralph Waldo Emerson once said, "People only see what they are 9 to see." If that's true, then it is also 10 that they only become what they are prepared to become. And many things in life is just about getting ready. "I want to be doing something more 11 with my life than what I am doing now," a young man once said to me. He 12 what he was doing was just not that important. Other people have said things to me such as, "I only 13 I had a meaningful relationship." And, "I'd really like to get a better job, but I just don't see 14 ." You fill in the blanks. What is it you would like to 15 that isn't happening? Perhaps the answer is that you are not yet 16 . Maybe you need more time to prepare before you are truly ready for that which you 17 . Think of today as another chance to 18 yourself for that exciting future you are looking for. Today is not washed. If you desire more from 19 , then you can use today as training. For you will experience only what you are prepared to 20 . Something wonderful can happen. And you can use today to get ready for tomorrow. | ||||
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