共查询到20条相似文献，搜索用时 140 毫秒
1.
程柱建 《数理天地(高中版)》2012,(10):38-38
1．两物体的初速度不等若两物体初速度不等,则两物体互为参考系时都是运动的,物体间必发生相对运动．2．两物体的初速度相同若两物体初速度相同,加速度也相同时,两物体将相对静止;加速度不同,则两物体的速度也不同,会发生相对运动． 相似文献
2.
方诚诚 《河北理科教学研究》2012,(3):24-25
带电粒子以某一速度垂直于电场线方向飞人匀强电场时,将受到与初速度方向垂直的恒定的电场力作用而做类似平抛的匀变速曲线运动．我们把曲线运动进行分解为沿初速度方向做匀速直线运动和沿电场力方向做初速度为零的匀加速直线运动． 相似文献
3.
《中学生数理化(高中版)》2017,(10)
<正>一、对基本概念的考查例1质点从同一高度水平抛出,不计空气阻力,下列说法正确的是()。A.质量越大,水平位移越大B.初速度越大,落地时竖直方向速度越大C.初速度越大,空中运动时间越长D.初速度越大,落地速度越大解析:质点做平抛运动,下落的时间由高度决定,由于从同一高度抛出,质点运动的时间相同,C错误;水平位移与初速度成正比,与质量无关,A错误;初速度是水平方向的速 相似文献
4.
1．粒子初速度的方向确定,大小变化
放大轨迹圆：根据初速度方向确定圆心所在的直线,逐渐放大粒子运动的轨迹圆,找到临界点． 相似文献
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6.
从匀变速直线运动的位移公式出发,从一般的情况入手,对它们做恰当的数学处理就可以构造出一系列的等差数列,它与初速度和加速度的具体值的大小无关,事实上也与初速度和加速度的方向无关。但是当仅考虑具体问题的计算时,所得的值是依赖于初速度和加速度的。 相似文献
7.
平抛运动是高中物理中重要的一种曲线运动模型,对平抛运动的研究方法是运动的合成与分解的典范,类平抛运动是平抛运动的拓展与延伸.类平抛运动的条件是合外力恒定、且与初速度垂直的匀变速曲线运动,它可分解为沿初速度方向上的匀速直线运动和垂直于初速度方向上的初速度为零的匀加速直线运动.它可模仿平抛运动的特点解决此类问题. 相似文献
8.
浅谈影响铁饼投掷远度的重要因素——出手初速度 总被引：2，自引：1，他引：1
投掷铁饼是田径运动中一项技术性比较强,以动态旋转为核心的运动项目。影响铁饼投掷远度的因素很多,其中铁饼出手初速度是至关重要的因素。本文通过文献综述的方法,探讨出手初速度对铁饼投掷远度的重要作用和各技术对出手初速度的贡献,这些会对改进技术,提高运动成绩,提供了理论依据。 相似文献
9.
均匀电磁场中带电粒子的运动学特性 总被引：1，自引：1，他引：0
通过对不同电磁场环境中的带电粒子受力情况研究带电粒子的运动规律.带电粒子只受电场或只受磁场作用时,其运动轨迹分别是抛物线或螺旋线.当带电粒子受电磁场作用时(带电粒子初速度、电场与磁场两两相互垂直或磁场垂直于初速度与电场构成的平面且初速度与电场成任意角度),得出带电粒子的运动方程. 相似文献
10.
掷实心球作为多年来的中考项目,在中学体育课堂教学中有着重要的位置.在体育教学过程中,投掷实心球是要求上下肢及腰腹肌协调配合,才能达到最有效的教学手段.
一、实心球项目特点
实心球是一项力量性和动作速度项目,是以力量为基础,以动作速度为核心的投掷项目.影响实心球成绩有三个因素,实心球的出手初速度、出手角度以及出手高度,其中出手初速度是最重要的因素.实心球出手初速度主要是由最后用力投掷球的距离和时间决定,用力距离越大,时间越短,则实心球的出手初速度就越大,出手初速度的能力主要取决于学生的身体素质发展水平及掌握正确的投掷实心球技术. 相似文献
11.
通过社会资本、人力资本和心理资本等三维资本,利用回归方法对高校毕业生初次就业满意度进行实证分析。人力资本对高校毕业生初次就业起着核心的配置性作用,实习经历显著影响着初次就业满意度;心理资本对初次就业满意度有着重要影响,乐观、自信可以显著提升初次就业满意度;社会资本广度对初次就业有着显著作用。高校毕业生利用资本的生产收益性,树立三维资本的投资理念,提升初次就业满意度;政府完善就业政策,限制社会资本的不公平逐利性,防止社会资本在市场竞争中滥用;高校加大就业帮扶,减少三维资本缺失带来的个体就业障碍。 相似文献
12.
英国通过“合格教师资格”（QTS）标准既规范了职前教师教育,又保证了教师专业化。作为职前教师教育的一部分,英国的信息通信技术教师的职前教育具有强调学科专业知识基础、注重职业信念培养、加强大学与中小学合作、提供多元化立体评价等特点,在我国高中信息技术教师培养策略方面,可以尝试其培养模式,借鉴其培养内容,强化专业体验,有针对性地对课程进行评价。 相似文献
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There exists a critical cyclic stress ratio when sand or clay is subjected to cyclic loading. It is an index distinguishing stable state or failure state. The soil static and dynamic universal triaxial and torsional shear apparatus developed by Dalian University of Technology in China was employed to perform different types of tests on saturated soft marine clay in the Yangtze estuary. Undisturbed samples were subjected to undrained cyclic vertical and torsional coupling shear and cyclic torsional shear after three-directional anisotropic consolidation with different initial consolidation parameters. The effects of initial orientation angle of major principal stress, initial ratio of deviatoric stress, initial coefficient of intermediate principal stress and stress mode of cyclic shear on the critical cyclic stress ratio were investigated. It is found that the critical cyclic stress ratio decreases significantly with increasing initial orientation angle of major principal stress and initial ratio of deviatoric stress. Compared with the effects of the initial orientation angle of major principal stress and initial ratio of deviatoric stress, the effect of initial coefficient of intermediate principal stress is less evident. Under the same consolidation condition, the critical cyclic stress ratio from the cyclic coupling shear test is lower than that from the cyclic torsional shear test, indicating that the stress mode of cyclic shear has an obvious effect on the critical cyclic stress ratio. The main reason is that the continuous rotation in principal stress directions during cyclic coupling shear damages the original structure of soil more than the cyclic torsional shear does. 相似文献
14.
虞晓骏 《江苏广播电视大学学报》2005,16(5):44-47
通过分析社会主义三次分配的特点、价值及伦理缺陷,可以得知：在和谐社会中,完整的分配过程要经历初次分配（经济领域）、再分配（政治领域）、第三次分配（社会领域）三个彼此区别、相互关联的阶段.其中,初次分配是分配过程的起点;政府再分配是对初次分配的矫正;作为“善”的第三次分配是对前两类分配必要的补充.社会主义和谐社会的分配正义正是在初次分配讲究效率,再分配注重公平,三次分配促进谐和的持续过程中得以实现. 相似文献
15.
This study investigated the contributions of initial literacy, oral language, and social adjustment to literacy achievement at the end of the kindergarten year. Data were collected across the kindergarten year from 48 children attending a school serving primarily children from low-income households with researchbased curriculum and intervention programs. Data were used to create latent variables to represent initial literacy, oral language, and social adjustment as predictor variables and a variable representing word reading and spelling as an outcome variable. Multiple regression indicated that only initial literacy contributed significantly to the outcome. Path analysis also indicated the significance of initial literacy while supporting the shared contribution of oral language to the literacy outcome. Discriminant function analysis indicated that individuals with higher scores on the literacy outcome had high factor loadings on both initial literacy and oral language. Social adjustment did not contribute significant variance to the literacy outcome in any of the analyses. This study has implications for both policy and practice, documenting the importance of initial literacy skills, even from the beginning of kindergarten, to kindergarten literacy outcome and highlighting the correlation between the effects of initial literacy and oral language on reading and spelling. 相似文献
16.
Fionnuala Waldron Janet Varley Colette Murphy Richard Greenwood 《Irish Educational Studies》2013,32(2):177-194
Research into student teachers’ perceptions, attitudes and prior experiences of learning suggests that these experiences can exert an influence on practice which can be relatively undisturbed by their initial teacher education. This article is based on the initial findings of an all-Ireland survey of all first-year students on B.Ed. courses in colleges in Northern Ireland and in the Republic of Ireland. The survey is the first stage in a longitudinal study which will follow the same cohort of students for the duration of their initial teacher education, seeking to map and track the development of their ideas about teaching and learning in primary history, geography and science. Based on an analysis of the quantitative data in the entry questionnaire, the initial findings suggest that subject knowledge remains a problematic issue in initial teacher education and that both location and gender interact with knowledge, attitudes and subject area to produce a complex and challenging context for teacher educators in history, geography and science education. 相似文献
17.
Philippe C. Duchastel 《Contemporary educational psychology》1981,6(3):217-226
Taking a test on a passage one has just studied is known to enhance later retention of the passing contents. This study examined the effects of three types of initial test on later retention: a short-answer test, a multiple-choice test, and a full free-recall test. Questions on the first two of these tests covered only half of the passage contents. Later retention was compared for both initially tested content and un-tested content with that of a control group not initially tested on the passage at all. The subjects were 57 secondary school students who studied a brief history text before taking one of the initial tests. All were given retention tests 2 weeks later. The classical testing effect (enhanced retention due to initial testing) was shown to be influenced by the type of initial test used. Thus, a testing effect was evident in the case of the initial short-answer test, but not in the case of either of the other two tests. A depth-of-processing view is advanced in interpreting this finding. The testing effect was found not to generalize to untested content and in one condition (the initial multiple-choice test), retention of untested content was depressed. 相似文献
18.
江昌龙 《黄山高等专科学校学报》2012,(5):7-10
根据质点在与平方成反比的有心力作用下运动的能量方程,结合初始条件求解出质点的运动学方程,系统分析初始条件的不同对运动结果的影响,确定以初始条件作为质点运动轨迹曲线类型的判据。 相似文献
19.
基于熵的K均值算法的改进 总被引：1，自引：0，他引：1
在高维数据中,K-means的相似度度量会遇到不同尺度、不同类型的数据等一些问题.本文提出了利用数据归一化预处理方法来改进K-means算法.在讨论一维数据初始中心点选取方法基础上,提出了基于熵的高维数据的初始中心点选取方法,通过对初始中心点选取方法的改进来减少K均值算法的迭代次数.实验结果表明,数据的归一化处理可以从根本上消除了数据类型的不一致对聚类的影响. 相似文献
20.
Jon Nixon Peter Cope James McNally Susan Rodrigues Christine Stephen 《International Studies in Sociology of Education》2013,23(3):243-261
The emphasis on 'partnership' in initial teacher education is a matter not just of organisational structure but of professional practices and purposes. If universities are to remain key players in initial teacher education, they must support the occupational group that represents the sector's interests and values: university-based initial teacher educators. Currently, however, this occupational group is awkwardly positioned between competing sets of accountability demands and institutional requirements. This article argues that only by encouraging and sustaining the professional renewal of university-based initial teacher educators will the university earn itself a continuing place in the evolving story of initial teacher education. That renewal is dependent, in other words, not only on the institutional re-positioning of the university but also on its re-commitment to initial teacher education as a core activity; a re-commitment which, it is argued, must recognise professional learning as a major 'field' of study across professional domains. 相似文献