题干

一位同学做平抛实验时,只在纸上记下重垂线у方向,未在纸上记下斜槽末端位置,并只描出如图所示的一段平抛轨迹曲线.现在曲线上取A,B两点,用刻度尺分别量出到у的距离,AA′=x1,BB′=x2,以及AB的竖直距离h,从而可求出小球抛出的初速度υ0为(  )

A:

B:

C:

D:

上一题 下一题 0.0难度 选择题 更新时间:2018-07-29 09:14:12

答案(点此获取答案解析)

A

同类题1

阅读理解

    Several days ago, Brenda had a car accident that led to one of her legs being cut off. Since then she didn't talk to anyone.

     “I wish I could bring her friends to visit her,” said Brenda's mother. “But it's a long bus trip.” The nurse smiled, “Don't worry. We have a plan.”

    Later that day, the nurse had taken Brenda to another room. “Here's your new roommate, Annie Wiggle-Do,” the nurse introduced a dark-hair teenager on the other bed.

    As soon as the nurse left, she jumped out of her bed with her only foot and sat at the other end of Brenda's bed, “I lost my leg from bone cancer,” she said. “What happened to yours?” Brenda was so shocked that she couldn't say a word. “You're lucky.” Annie continued. “You've still got your knee. They had to take mine.”

     “I'd like to have a chat with you, but my friends are coming any time now, so I have to get ready.” Annie said when she took off her hair! Her head was completely bald(秃头的).

     “Oh, I forgot to tell you, the medicine they gave me to kill the cancer also killed my hair.” Annie looked out her wigs(假发), brown and yellow, short and long, straight and curly.

     “That's why I thought up ‘Annie Wiggle-Do'.” Annie smiled. “Get it? Any wig will do? Annie Wiggle-Do?” “When Annie's friends came, she introduced Brenda to them all. Before long, Brenda started chatting with Annie and her friends. They didn't make her feel like a strange person at all!

    The girls shared their names with each other. When it was time to go to bed, Brenda said, “Good night, Annie-Wiggle-Do. Can't wait till morning.”

同类题3

阅读下面的文言文,完成文后各小题。

    薛居正,字子平,开封浚仪人。父仁谦,周太子宾客。居正少好学,有大志。清泰初,举进士不第,为《遣愁文》以自解,寓意倜傥,识者以为有公辅之量。逾年,登第。汉乾祐初,史弘肇领侍卫亲军,威权震主,残忍自恣,无敢忤其意者。其部下吏告民犯盐禁,法当死。狱将决,居正疑其不实,召诘之,乃吏与民有私憾,因诬之,逮吏鞫之,具伏抵法。弘肇虽怒甚,亦无以屈。周广顺初迁比部员外郎领三司推官旋知制诰周祖征兖州诏居正从行以劳加都官郎中。显德三年,迁左谏议大夫,擢任判馆事。六年,使沧州定民租。未几,以材干闻于朝,擢刑部侍郎

    宋初,迁户部侍郎。建隆三年,入为枢密直学士,权知贡举。初平湖湘,以居正知朗州。会亡卒数千人聚山泽为盗,监军使疑其城中僧千余人皆其党,议欲尽捕诛之。居正以计缓其事,因率众剪灭群寇,擒贼帅汪端,诘之,僧皆不预,赖以全活。

    乾德初,加兵部侍郎。车驾将亲征太原,大发民馈运。时河南府饥,逃亡者四万家,上忧之,命居正驰传招集,旬间民尽复业。开宝八年二月,上谓居正等曰:“年谷方登,庶物丰盛,若非上天垂祐,何以及斯。所宜共思济物,或有阙政,当与振举,以成朕志。”居正等益修政事,以副上意焉。

    太平兴国六年,因服丹砂遇毒,方奏事,觉疾作,遽出。至殿门外,饮水升余,堂吏掖归中书,已不能言,但指庑间储水器。左右取水至,不能饮,舆归私第卒,年七十。

    居正气貌瑰伟,饮酒至数斗不乱。性孝行纯,居家俭约。为相任宽简,不好苛察,士君子以此多之。自参政至为相,凡十八年,恩遇始终不替。

(选自《宋史·薛居正传》,有删改)

【注】①鞫:审问。