北半球抛体运动的研究

考虑地球自转效应时,一般理论力学教材中,依据非惯性参考系中北半球自由落体的动力学方程,略去ω的高阶项,给出自由落体的东偏值。利用解析的方法求出北半球抛体的运动学方程,并自然地得到自由落体的东偏值。     

动能定理的参考系

本人根据动能定理应用的相关练习在课堂教学中即时生成的问题，敏锐觉察到学生对动能定理参考系选择只是习惯性选择地面进行求解，但并没有深刻认识到运用动能定理需要选择同一惯性参考系的原因.为此，本文从动能定理的推导重新阐述需要选择同一惯性参考系的逻辑理由，并且让学生开阔视野，提升物理学习兴趣，让学生了解了在非惯性系下应用动能定理解决问题的方法，提升学生的物理学科素养.     

万有引力与重力的关系

"万有引力定律及其应用"是中学物理的主干知识点,可是中学生往往对万有引力与重力关系中的一些问题感到困惑。本文采用中学物理和大学物理知识,即在惯性参考系和非惯性参考系中对万有引力与重力关系做了仔细分析和深入讨论。把地球当作惯性参考系时,重力为万有引力的分力,向心力只占万有引力的很小一部分。重力和重力加速度随纬度的升高而增加,在南北两极最大,在赤道上最小。重力的竖直方向随纬度的变化而变化,它不是垂直于与地面相切平面的方向。地球在自转,是一个非惯性参考系,在非惯性参考系中,万有引力为重力的分力,在两种参考系中分析出的重力不变。     

利用非惯性参考系求解高中物理典型习题初探

利用惯性参考系求解高中物理习题是广泛认可的基本思路,源于牛顿经典力学知识体系的局限性,也同样强化了这一基本思维。对于部分典型习题,如相对运动求解位移、时间、加速度等,若选用非惯性参考系求其解较选用惯性参考系方便且高效。但利用非惯性系求解物理问题需要教师考量实际情况,切不可盲目针对任何学生,任何学习阶段进行运用。     

从相对性原理看位移与功的相对性

众所周知,牛顿动力学规律适用于惯性系．当从一种惯性系转变为另一种惯性系时,牛顿定律的形式将不发生改变,即牛顿定律在任何惯性参考系面前都是平等的或平权的．也可以说对于描述力学规律来说,一切惯性系都是等价的．这叫力学的相对性原理或伽利略相对性原理．在一般力学教材上只是指出了速度、位移和功都具有相对性,但都没有给出具体的详细讨论,本文从几个物理量方面讨论他们的相对性关系．     

浅议“机械能”中的力学相对性原理

学习完机械能一章后,学生提出这样的问题：动能大小由m和u值来决定,而。的大小与参考系选取有关,那么动能的大小是否也和参考系的选取有关呢？在地面参考系中成立的动能定理在其他惯性参考系中是否依然成立？对第一个问题,我给予了肯定的答复：物体动能的大小与参考系的选取有关,在不同参考系中同一时刻测同一物体的速度值是不同的,因而动能值也必然不同．在得到第一个问题的答复之后,学生迫不及待地给出了第二个问题的答案：动能定理在相对地面运动的其他惯性系中不成立,而且还给出了如下证明（显然学生是有备而来）：     

动生、感生电动势与相对论的关系

本文讨论了动生、感生电动势与相对论的关系,指出了二者具有相对性,并且讨论了两种电动势通过参考系的适当变换而实现归一化的问题。     

非惯性系视域下地表附近的自由落体加速度

忽略空气阻力,地表附近的物体自由下落时的加速度通常被认为其等于重力加速度。地表附近的物体下落的加速度也普遍认为与其本身质量无关。在严格意义上,地球并非严格的惯性系,由此便可推导得出,地表附近的物体自由下落的加速度并非与物体质量无关,只有当物体质量远小于地球时才可近似认为与其质量无关。     

科里奥利加速度的推导及物理分析

科里奥利加速度在普通物理力学中是一难点。本文就一质点相对于惯性系运动的同时也相对于运动参考系运动的情况 ,由浅入深地推导出了科里奥利加速度公式 ,分析了其产生的物理原因     

碰撞过程的平衡解法

本文通过引入惯性冲量,将刚体碰撞过程的动力学问题,从形式上转化为作用在刚体上冲量系的平衡问题。从而使碰撞过程的求解问题,转化为求解一组平衡方程组。     

Students’ Perceptions of Dynamics Concept Pairs and Correlation with Their Problem-Solving Performance

A concept pair is a pair of concepts that are fundamentally different but closely related. To develop a solid conceptual understanding in dynamics (a foundational engineering science course) and physics, students must understand the fundamental difference and relationship between two concepts that are included in each concept pair. However, all existing research in dynamics and physics education has been focused on the identification and repair of students?? misunderstanding of individual concepts, but not concept pairs. The present research fills the gap of existing research by studying students?? perceptions of dynamics concept pairs and correlation with their problem-solving performance in both particle and rigid-body dynamics. A total of 88 engineering undergraduate students participated in the present study. Students?? perceptions were assessed using a 40-item instrument that included 20 dynamics concept pairs at fundamental Level One and higher-order Level Two. Students?? problem-solving performance was assessed using four exams that included 66 dynamics problems. The coefficients of reliability (Cronbach??s ??) of assessment instruments vary between 0.69 and 0.93. The research findings from the present study show that students were not confident in their understanding of Level-Two concept pairs, especially the relationship between the Principle of Linear Impulse and Momentum and the Principle of Angular Impulse and Momentum, and the relationship between the Principle of Angular Impulse and Momentum and the Conservation of Angular Momentum. A statistically significant correlation exists between students?? perceptions of Level-Two concept pairs and their problem-solving performance on both particle dynamics (r?=?0.355, p?<?0.01) and rigid-body dynamics (r?=?0.351, p?<?0.01). The research findings made from the present study imply that educational efforts should be focused on improving students?? understanding of Level-Two dynamics concept pairs.     

Promoting Inclusive Communities in Diverse Classrooms: Teacher Attunement and Social Dynamics Management

Classroom social integration with peers is vital to students’ school success, and all students can benefit from contact with peers who are different in various ways. Teachers are uniquely positioned to support the social adaptation of diverse learners but require an understanding of classroom dynamics. Moreover, teachers need strategies that help to leverage positive peer dynamics and that promote an engaged classroom climate for all students. Reflecting a person-in-context perspective, this review discusses the peer relations and social adjustment of students, particularly in classrooms with a diverse range of student characteristics and instructional needs, and proposes that teachers’ use of social dynamics management strategies can foster classroom communities that support the involvement and adjustment of all students.     

群体动力对英语自主学习的影响研究

研究选了有着类似学习背景的大二、大三各两个班级的学生作为研究对象,先进行问卷调查得到他们群体动力和自主学习的数据,然后对各组数据进行比较分析,最后选了16位同学进行访谈。研究发现:群体动力对学习者的自主学习行为有着显著影响,但和自主学习的责任感无关;学习者自己的意志是影响自主学习的重要因素;年龄在群体动力对自主学习的影响中也起着一定的作用。本研究丰富了群体动力理论,阐明了群体动力在英语自主学习中的重要性。     

Doctoral students’ experiences of nondisclosure with their dissertation chair

We examined doctoral students’ experiences of nondisclosure with their dissertation chairs. Using a hermeneutic phenomenology design, we analyzed two individual interviews of 10 doctoral students. We identified the following three themes: (a) the professional dynamics in the relationship, (b) the interpersonal and cultural dynamics in the relationship, and (c) prioritization of completing the dissertation. Implications for doctoral students and dissertation chairs are discussed.     

What Makes a Student Group Successful? Student-Student and Student-Teacher Interaction in a Problem-Based Learning Environment

This study investigated student-student and teacher-student interaction in a problem-based course and looked at study success in relation to group dynamics and approaches to studying. Data for this study were provided by 31 law students who were enrolled in a course in legal history at the University of Helsinki in February 2001. The students were divided into three small groups that were tutored by one teacher. Both the students and the teacher were interviewed. The interaction between the students and their teacher, and the group dynamics of each subgroup, were observed during the tutor sessions. The results showed that the student groups were very different from each other in terms of study success, group dynamics and communication between the group members. One group achieved significantly higher grades than the other two groups. There was only one clear difference between the three groups. The interviews and observations showed that the students in the best group participated more evenly and actively in the discussions than students in the other two groups.     

中国“十四五”教育规模的预测研究:基于系统动力学模型

采用科学方法对教育规模进行预测,有助于为教育发展的目标制定、教育结构优化和教育资源配置提供参考。该研究采用系统动力学模型,综合考虑人口、经济、科技因素与教育系统之间的作用关系,对中国“十四五”时期各级各类教育规模进行预测,发现:学前教育适龄人口在2021年后,逐年降低,预计到2025年,中国在园幼儿数不足4400万人;九年义务教育在校生数将在2024年开始下降,2025年为14415万人;高中阶段教育规模基本稳定,在校生(不含技工学校)达到4085万人;高等教育规模稳步上升,2025年在校生达到3930万人,其中,在校研究生数(不含非全日制)达到349万人。教育主管部门应将规模变化作为学前教育普惠普及、义务教育高位优质均衡、高中教育特色发展、高等教育内涵式发展的重要契机,建设高质量教育体系。     

抗震动力学课程网络教育平台探析

夯实动力学课程的理论水平与数值分析技能,是开展水工抗震领域相关研究的重要基础。然而,动力学概念与分析手段对于许多高年级本科生或硕士研究生来说,都显得过于复杂,难以在短时间内领悟,一定的怠学情绪存在于课堂教学中。本文拟从拓展教学手段的角度出发,尝试探讨网络平台教育的可行性,对该问题做一分析,在生动地拓展同学知识面的同时,激发学习热情,为实现教育教学资源的高水平立体化而服务。     

Does teaching students how to explicitly model the causal structure of systems improve their understanding of these systems?

If students really understand the systems they study, they would be able to tell how changes in the system would affect a result. This demands that the students understand the mechanisms that drive its behaviour. The study investigates potential merits of learning how to explicitly model the causal structure of systems. The approach and performance of 15 system dynamics students who are taught to explicitly model the causal structure of the systems they study were compared with the approach and performance of 22 engineering students, who generally did not receive such training. The task was to bring a computer-simulated predator-and-prey ecology to equilibrium. The system dynamics students were significantly more likely than the engineering students to correctly frame the problem. They were not much better at solving the task, however. It seemed that they had only learnt how to make models and not how to use them for reasoning.     

Power Dynamics and Questioning in Elementary Science Classrooms

We describe the dynamic discourse interactions between a teacher and her students in a third-grade science classroom. We focused on how the teacher and students initiate, prompt, respond, and provide feedback; use questioning and power strategies; and how questions are associated with power dynamics. We relate the consequences of teacher use of power to the engagement of student with subject matter. Two classroom sessions were observed and teacher?Cstudent interactions audio recorded. Data were transcribed and a method was developed for analyzing teacher-student interactions, power dynamics, and types of questions asked. Results revealed that teacher talk was twice as frequent as students?? talk; questions were primarily closed-ended and task-oriented; and students asked few questions. The teacher exercised power by keeping activities organized and conventional, and utilizing subject matter. The developed methods showed us the complexity of question and power dynamics in classroom discourse and have implications for professional development and research.     

Power dynamics with international students: from the perspective of domestic students in Korean higher education

This paper explored the power dynamics between domestic and international students in the context of higher education in an Asian non-English speaking country, Korea. Despite increased international student mobility in recent years, little is known about the relationship dynamics among students from different countries, especially related to power issues. The findings in this study suggested that international students’ countries of origin and language of communication created different power statuses compared to Korean students by their empowerment and discrimination. Power differentials also existed among Korean students due to variations in their English ability to interact with international students. Conversely, international students’ attitudes and acceptance influenced Korean students’ attitudes toward them, irrespective of power differentials created by countries and language, as perceived by Korean students. The implications related to the recent trend of international student mobility are discussed.