题干

建立模型是解决物理问题的一个重要方法,下列选项中不属于理想化模型的是(    )

A:电子

B:质点

C:匀速直线运动

D:不可伸长的绳子

上一题 下一题 0.0难度 选择题 更新时间:2019-01-30 03:33:48

答案(点此获取答案解析)

A

同类题2

阅读下面的文言文,完成小题。

    赵延进,澶州顿丘人。父晖,周太子太师。尝与乱军入民家,少年同行者竞取财贿,延进独持书数十编以归,同辈哂之。

    汉末,晖领凤翔节度,未赴镇,王景崇据城反,命晖为都招讨使击之。延进年十八,屡当军锋。睢阳有盗数百,各立酋帅,为民患。延进以父命,领牙兵千余悉禽戮之,诏书褒美。

    宋初,迁右羽林军将军、濠州都监。会伐蜀,以襄州当川路津要,命为钤辖、同知州务。蜀平,专领郡事。汉江水岁坏堤,害民田,常兴工修护,延进累石为岸,遂绝其患,入为两浙、漳泉国信使。太平兴国中,大军平并州,讨幽蓟,皆为攻城八作壕砦使①。尝诏督造炮具八百,期以半月,延进八日成。太宗亲试之,大悦。

    辽人扰边,命延进与崔翰、李继隆将兵八万御之,赐阵图,分为八阵,俾以从事。师次满城辽骑坌至延进乘高望之东西亘野不见其际翰等方按图布阵阵去各百步士众疑惧略无斗志。延进谓翰等曰:“今敌众若此,而我师星布,其势悬绝,彼若持我,将何以济!不如合而击之,可以决胜。主上委吾等以边事,盖期于克敌尔。违令而获利,不犹愈于辱国乎?”翰等曰:“万一不捷,则若之何?”延进曰:“倘有丧败,则延进独当其责。”于是改为二阵,前后相副。三战,大破之。

    及代,吏民数千守阙借留,诏许留一年。淳化初,飞蝗不入境,诏褒之。咸平二年卒,年七十三,赠左武卫上将军。

    延进姿状秀整,涉猎经史,拳勇有谋,士流以此多之。延进妻即淑德皇后之妹,故在显德、兴国中,颇任以腹心。子昂,太平兴国二年登进士第,至户部郎中、直昭文馆。

(节选自《宋史》)

【注】①攻城八作壕砦使:负责后勤的官职名,砦,同“寨”。

同类题3

阅读下列内容, 从每小题所给的 A、B、C、D 四个选项中选择一个最佳答案。

Who is the greatest teacher in Chinese history? Many people would think of Confucius(孔子), whose birthday was September 28. Although he lived over 2, 000 years ago, people still remember and respect him for his contribution(贡献) to the education today.

Confucius lived in the Kingdom of Lu, which lies in Shandong Province. He lived during the Spring and Autumn Period. He had a hard childhood. His father died when he was only 3. His mother brought him up. As a child, he had to work to help his mother, but young Confucius didn't give up studying. He visited many famous teachers and learned music, history, poetry and sports.

Later, he became a teacher and started the first public school in Chinese history. At that time only children from noble families could go to school, but Confucius believed everyone should go to school if they wanted to learn. He had about 3, 000 students in his lifetime.

Today, people still follow Confucius' lessons. He told us that we all have something worthy to be learned. “When I am with three people, one of them must be better than me in some areas. I choose their good qualities and follow them.”

He also taught us that thinking is very important in study. “All study but no thinking makes people puzzled (困惑的). All thinking but no study makes people lazy.” Confucius is not only a great teacher, but also a famous thinker with wise thoughts about the world and society. His most important teachings are about kindness and good manners. “A person should be strict with himself, but be kind to others.” he said.