您所在的当前位置：高中物理试题 >

匀变速直线运动

> (12分) 列车正以v 0=30m/s的速度行驶，接到前方小站的请求在该站停靠1min，接一个危重病人上车．司机决定匀减速运动到小站，用时间50s。停车1min后列车又匀加速启动，经30s恢复到原来的速度行驶．试求列车进站和出站的加速度。

问题：

发布时间：2024-09-12

(12分) 列车正以v ₀=30m/s的速度行驶，接到前方小站的请求在该站停靠1min，接一个危重病人上车．司机决定匀减速运动到小站，用时间50s。停车1min后列车又匀加速启动，经30s恢复到原来的速度行驶．试求列车进站和出站的加速度。

参考答案：

提问用户：a2***H9F

可能感兴趣的题目：

1 函数 y=cos(2x- 5π 6 )的最小正周期是（　　） A． π 2 B．π C．2π D．4π
2 甲、乙两人进行百米赛跑时，甲到终点时，乙还在离终点10m处，现让甲的起跑线后退10m，各人以原来的速度再进行比赛，则先到达终点的是 A.乙先到达 B.甲先到达 C.同时到达 D.无法比较
3 下列各组物质之间不能发生置换反应的是 A．氯水加入溴化钠溶液中 B．溴水加入氟化钠溶液中 C．氯水加入碘化钾溶液中 D．溴水加入碘化钾溶液中
4 The problem ________ at the meeting yesterday. A．came to B．came across C．came up D．came up with
5 阅读理解。 Just as adults have a hard time putting down their iPhones, so the device is now the toy of choice for many 1- 3 years old children. It"s a phenomenon that is attracting the attention of some childhood development specialists. Natasha Sykes, a mother of two in Atlanta, remembers the first time her daughter, Kelsey, then barely 2 years old, held her husband"s iPhone. "She pressed the button and it lit up. I just remember her eyes. It was like "Whoa!" "The parents were charmed by their daughter"s fascination. But then, said Ms. Sykes, "She got serious about the phone."Kelsey would ask for it. Then she"d cry for it. "It was like she"d always want the phone," Ms. Sykes said. Apple, the iPhone"s designer and manufacturer, has built its success on machines so simple and intuitive(直观的) that even technologically confused adults can figure out how to work them, so it makes sense that expert children would follow. Tap a picture on the screen and something happens. What could be more fun? Many iPhone on the market are aimed directly at preschoolers, many of them labeled "educational," such as Toddler Teasers: Shapes, which asks the child to tap a circle or square or triangle; and Pocket Zoo, which broadcasts live video of animals at zoos around the world. There are "flash cards" aimed at teaching children to read and spell, and a "Wheels on the Bus" program that sings the popular song in multiple languages. Then there"s the new iGo Potty program, with automated phone calls reminding toddlers that it"s time to "go ". Along with fears about dropping and damage, however, many parents sharing iPhones with their young ones feel guilty. They wonder whether it is indeed an educational tool, or a passive amusement like television. The American Academy of Pediatrics has long advised parents not to let their children watch any TV until they are past their second birthday. Jane M. Healy, an educational psychologist in Vail, Colo. said: "Any parent who thinks a spelling program is educational for that age is missing the whole idea of how the preschool brain grows. What children need at that age is whole body movement, the skills of playing lots of objects and not some difficult technology. You"re not learning to read by lining up the letters in the word "cat." You"re learning to read by understanding language, by listening." 1. The main purpose of Kelsey referred to in the passage is to ____. A. not only adults but children are crazy about iPhones B. encourage people to buy this toy for their children C. advertise for the toy D. show Kelsey likes the toy very much 2. The underlined words "it"s time to "go" "in Paragraph 3 mean ______. A. it"s time to stop playing the toy B. it"s time to go to sleep C. it"s tie to go to the washroom D. it"s time to go home 3. The parents asking their young children to play iPhones feel guilty because _____. A. they know the toy has a negative effect on them B. the children damage the toy C. they are not sure of the real effect of the toy D. they ask their children to watch live video of animals 4. In Jane"s mind, in educating preschoolers parents should _____. A. buy this toy for their children. B. ask their children to play as many toys as possible C. ask their children to learn a spelling program D. know how the preschool brain grows
6 此图为我国重要的商品粮基地，由图中提供的信息分析回答：（13分）（1）分析三基地发展共同的有利自然条件。（4分）（2）比较A、B、C三地在耕作制度和主要农作物上的差异，并填写下表：（9分）
7 香港的经济支柱是 A.赌场收人 B.对外贸易 C.农业 D.旅游业
8 (2013·合肥模拟)— 　　　　bargaining is so interesting? —Sometimes it is a test to see who can stand their ground for the longest. A．What is it that B．Why is it that C．What it is that D．Why it is that
9 A、B两车与水平地面的动摩擦因数相同，则下列说法正确的是( ) A.若两车动量相同，质量大的滑行时间长 B.若两车动能相同，质量大的滑行时间长 C.若两车质量相同，动能大的滑行时间长 D.若两车质量相同，动量大的滑行距离长
10 过的焦点的直线交抛物线与两点，求