已知某航空母舰飞行甲板长度为L=300m，某种战斗机在航空母舰上起飞过程中最大速度为a=4.5m/s2，飞机速度要达到v=60m/s才能安全起飞。
（1）如果航空母舰静止，战斗机被弹射装置弹出够开始加速，要保证飞机安全起飞，战斗机被弹射装置弹出时的速度至少是多大？
（2）如果航空母舰匀速前进，在没有弹射装置的情况下，要保证飞机起飞安全，航空母舰前进的速度至少是多大？
(1) v0=30m/s；(2) v=8.04m/s
题目分析：
(1)根据v2-v02=2as得v0=30m/s
(2)飞机在航空母舰上具有和航母一样的速度,所以用相对速度解起来容易点.(60-v)2=2as
得v=8.04m/s
| 阅读理解。 | |||||
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| 1. How many rules are there in the competition? | |||||
| A. One. B. Two. C. Three. D. Four. | |||||
| 2.What kind of stories can get high marks? | |||||
| A. A story of more than 200 words. B. A story sent before July 1. C. A story which is creative. D. A story written by a junior middle school student. | |||||
| 3. When must the stories be handed in? | |||||
| A. By the end of the term. B. By the end of the month. C. When you got the information. D. On July 1st. | |||||
| 4. What will the first prize winner get? | |||||
| A. 2 000 yuan. B. 1 000 yuan. C. 500 yuan. D. 300 yuan. | |||||
| 5. Which of the following statements is NOT TRUE according to the passage? | |||||
| A. The stories can be written with the help of your parents. B. The stories can only be sent by e-mail. C. All winners will get an e-mail to be informed of the news. D. The judges are English teachers from six schools. |