如图所示,是探究“动能的大小与什么因素有关?”实验的示意图。小球从a处滚下,在c

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问题:

如图所示,是探究“动能的大小与什么因素有关?”实验的示意图。小球从a处滚下,在c处与小木块碰撞,并与小木块共同运动到d处停下。下面的一些判断正确的是

[ ]

A.从a到b,小球的势能不变,动能增大

B.从b到c,小球的势能增大,动能增大

C.到达c处,小球的势能最小,动能最大

D.到达d处,小球的动能为零,小木块的动能最大

考点:动能的影响因素
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患者,男性,57岁,嗜烟约35年。慢性咳嗽咳痰10余年,进行性气促加重2年,被诊断为慢性支气管炎、阻塞性肺气肿,其X线胸片不会出现下列哪项().

A.早期正常无明显变化,中、晚期可见肺纹理增加、粗乱

B.合并感染时有支气管周围炎症改变

C.合并感染时有支气管柱状扩张,肺纹理蜂窝状改变

D.肺容量增大,肋间隙增宽,膈肌低平

E.心脏悬垂并狭长

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下列关于税务咨询的陈述,正确的有( )。

A.税务咨询受托主体具有独立性和咨询方式多样性的特点

B.税务咨询结论具有一定的权威性,税务咨询报告是税务机构征税的一个依据

C.签订咨询协议属于税务咨询业务流程的内容,发生在税务咨询的具体操作规范之前

D.税务咨询的形式中,最常用的是书面咨询

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下列对中国人在改革开放后生活状况的描述,不正确的是  [ ]

A.购买食品、布料凭粮票、布票

B.国家启动“安居工程”

C.国有企业改革中出现下岗职工

D.医疗保险制度启动

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试述手指掌乳突花纹中的细节(细小)特征。

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The produce departments of the future may look like nothing on earth, and with good reason. Chinese scientists have been growing tomatoes the size of softballs, cucumbers as long as baseball bats and other outsize fruits and vegetables, using seeds that have been shot into space. The seeds are then exposed to seven types of extraterrestrial conditions, from zero gravity and cosmic radiation to subatomic particles. (46) As these space veggies grow back on earth, they are selected for desirable traits--bulk, appearance or certain nutrients--then bred through successive generations to ensure that the mutations are consistent.

Chinese scientists don’t understand exactly how a trip into space alters the seeds’ DNA and yields such effects, but it’s not just size that changes. (47) Tong Yichao, whose firm, the Beijing Flying Eagle Green Foods Group, has been sending seeds and seedlings aboard Chinese spacecraft since 1999, says it has grown space tomatoes with 27 percent more of the antioxidant beta carotene than ordinary ones, and six-foot-tall cotton plants that produce longer, more flexible threads. Using conventional methods, "a scientist might create just three new plants in his lifetime," says Tong. "We’ve developed more than 50 since 1999."

(48) A dozen or so Chinese firms are paying up to $ 45 000 a gram to place various flora aboard satellites and manned spacecraft. The long-term goal: to feed more people and help endangered species escape extinction. To date, nearly 3 000 botanical species-including garden vegetables, medicinal herbs and flowers--have been sent into orbit and brought back to earth.

(49) The commercial promise of China’s space veggies has yet to, er, bear fruit. It’ s legal to sell the cosmic produce, and commercial farms have purchased some space plants. But most are being developed in labs or experimental greenhouses because no one wants to go to market before the safety and quality of the produce have been established. Even so, the idea of space flora is proving irresistible to a novelty-loving Chinese public. (50) When Tong displayed a handful of monster space eggplants--the largest of which weighed more than four pounds--at an expo, one disappeared before the show opened. Hot stuff, for sure.

(49) The commercial promise of China’s space veggies has yet to, er, bear fruit.

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