题干

滑雪运动员由斜坡高速向下滑行时其速度—时间图象如图所示,则由图象中AB段曲线可知,运动员在此过程中

A:机械能守恒

B:做匀加速运动

C:做曲线运动

D:所受力的合力不断减小

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答案(点此获取答案解析)

D

同类题1

阅读材料,回答问题

材料一:东汉河南郑兴家族简况(据《后汉书》整理)

材料二:两宋时期社会政治经济关系的变迁,使“今骤得富贵者,止能为三四十年之计”,“千年土地八百主”,高官大族也可能“家世零替”。如何整合族人、延续世系、复兴宗法成为宋代士大夫面临的共同难题。于是,以建宗祠、置族田、修宗谱、定族规、立族长为主要特征的宗法家族制度得以全面复兴。

    按照宗法制度,在祠堂祭祀中应当按辈分排列祖先的地位。但清代早期,江苏宜兴任氏祠堂家祭的对象,除一族祖先之外,其次即是官员和有钱财的人,再次则是所谓有一善一行的人,最后才是本宗族的一般平民祖先。此类现象并非个例,所以引起了当时卫道之士的批评。

──据袁行霈《中华文明史》等

材料三:如图所示是某学习小组研究“1927﹣1929年中共武装起义与宗族组织”时提出的论证思路:

材料四:1984年11月,国家档案局、教育部和文化部联合发出《关于编好<中国家谱综合目录>的通知》,指出“家谱是我国宝贵文化遗产中亟待发掘的一部分”,修谱、续谱之风在各地悄悄兴起。近二十年尤其是2000年后的近十年中,民间新修族谱大量出版。新修族谱中,妇女也可填名入谱,入继、入赘、改嫁、非婚生子嗣等入谱基本全部放弃了传统“义例”中的严厉规定,基本不再有各宗之间因大小宗、因外娃子嗣的“名分”、因族产祀田归属争得你死我活的现象。地方政府也公开编写某些姓氏谱牒,比如,编《太原王氏》,起因是为了缅、泰华侨的热烈需求,编汾阳郭氏资料是为了郭台铭和富士康。上月河南新郑在中央某大报上登整版“黄帝公祭大典”消息,下面排的是29个本地招商项目。

──据《民间修家谱热调查》

同类题2

        A high school history teacher once told us, “If you make one close friend in school, you will be most fortunate. A true friend is someone who stays with you for life."1 teaches that he was right. Good friendship is just not easily 2

        It is possible that we simply do not stay in one place long enough food 3friendship to4. However, there can be5disagreement on the need for each of us to think carefully about the kind of friendship we want.

        To most of us, friendships are considered very important, but we need to have clear in our 6 the kinds of friendship we want. Are they to be close or7at arm's length? Do we want to 8ourselves or do we want to walk on the surface? For some people, many friendships on the surface are 9enough—and that' s all right. But at some point we need to10that our expectations are the same as our friends' expectations. The sharing of11experience 12our tears as well as our dark dreams is the surest way to deepen friendships. But it 13be undertaken(进行) slowly and carried on only if there are 14of interest and action in return.

          What are some of the 15of friendship? The greatest is the attraction to expect too much too soon. Deep relationships 16time. Another“major difficulty" is the selfishness to think one “possesses" the other, including his time and attention. Similarly, friendships 17actions in return. In 18words, you must give as much as you take. Finally there is a question of taking care of. Unless you spend 19time together, talking on the phone, writing letters, doing things together, friendships will die20.