摩擦力演示装置

为了辅助摩擦力的教学,自制了摩擦力演示装置,通过模拟电路与数字电路的转换可以直接显示出滑块与传送带间的摩擦力.该装置不仅可以探究静摩擦力和滑动摩擦力,而且还可直观地显示出物体间摩擦力的渐变过程.     

费尔德常数到底有多大?

当线偏振光穿越媒质时,由于沿传播方向的磁场影响,振动面将要转动。这种现象称为法拉第效应或磁光效应。振动面旋转的角度θ由以下经验公式给出: θ=VBd,式中B为磁感应强度,d为穿越媒质的长度,比例系数V称为费尔德(Verdet)常数,其数值由实验测定。 我们比较了国内外出版的手册和书籍所列出的费尔德常数值,发现出人颇大,有的甚至差几个量级。有些书中的数值相同,但单位不同。换算成同一单位,则大小就相差甚远了。可见把单位搞错,也可能是以讹传讹的原因之一。经笔者核对,文献[1][2][3]所给的V值彼此相符,可认为它们是正确的。由于各方面条…     

摩擦力作功及摩擦生热分析

本文从力学与热力学两个方面综合分析了摩擦力作功与摩擦生热过程。澄清了由于从力学单方面考虑这一问题而产生的某些模糊认识。     

关于动滑轮中摩擦力的讨论

在直线运动中，静摩擦力和滑动摩擦力的作用及做功问题，已有明确结论．这些结论是：一对静摩擦力做功之和为零，所以有（一对）静摩擦力存在不会引起机械能的改变；一对滑动摩擦力做功之和一定不为零，所以有（一对）滑动摩擦力存在一定伴随着机械能转化为热（内能）的过程，     

摩擦力的实验研究与设计

设计了3个研究摩擦力的实验,直观地演示了摩擦力的特点和性质.     

直观显示摩擦力实验的改进

对文献^[1]中用弹簧秤直观显示摩擦力的实验进行了改进，成功地解决了原实验在滑动摩擦力的测量过程中不易读数的问题。     

半自动化摩擦力测量装置设计

设计了摩擦力测量及数据显示装置.该装置由数据采集模块、动力装置模块和摩擦发生模块构成.应用直流有刷电机、拉力传感器、数字量变送器、USB转485转换器和电脑上位机软件设计的一种新型的半自动化摩擦力测量装置,实现对摩擦力的精准简便测量.该装置操作便捷、测量精度高、数据显示直观,可以应用于中学物理教学,也可以为工业生产中相...     

冲击作用下的摩擦力效应实验研究

针对摩擦力效应产生的机理, 本文设计了三种不同尺寸的试件进行SHPB实验, 得到了摩擦力效应对实验的定量影响, 在此基础上对混凝土的DIF进行了修正研究, 为混凝土抗冲击工程设计提供了参考依据. 关键词： 冲击 混凝土 SHPB 摩擦力     

海森伯模型的谱,到底有多靠谱?

正1缘起靠谱,还是不靠谱,这是一个值得思考的问题。这个问题不仅关乎哈姆雷特对于人生悖论的追问,其实在凝聚态物理学量子多体问题的动力学性质计算中,也是一个让多少仁人志士扼腕叹息的、带有希腊悲剧意味的、形而上的命题。所谓动力学性质,主要是指谱     

How Einstein Did Not Discover

What powered Einstein’s discoveries? Was it asking naïve questions, stubbornly? Was it a mischievous urge to break rules? Was it the destructive power of operational thinking? It was none of these. Rather, Einstein made his discoveries through lengthy, mundane investigations, pursued with tenacity and discipline. We have been led to think otherwise in part through Einstein’s brilliance at recounting in beguilingly simple terms a few brief moments of transcendent insight, and in part through our need to find a simple trick underlying his achievements. These ideas are illustrated with the examples of Einstein’s 1905 discoveries of special relativity and the light quantum.     

静摩擦力方向的判断法

判断静摩擦力方向是高中物理教学的难点.新编高中物理第10页指出:"静摩擦力的方向总跟接触面相切,并且跟物体相对运动趋势的方向相反".判断静摩擦力的方向,关键在于找出物体相对运动趋势的方向.     

如何指导学生掌握物理概念

物理概念的掌握是对已有物理概念的一个有组织的学习过程,它虽不像科学史上物理概念的建立那样曲折漫长,但都是认识客观世界的过程,都得遵循相同的认知规律:从感性(感觉、直觉、表象)通过分析、综合、抽象、概括到理性认知.也就是说,学生对物理概念的掌握也需要经历从具体到抽象、从感性到理性、从模糊到精确、从简单到系统的发展过程.在中学物理教学过程中,如何通过教学设计来让学生经历上述过程有效地掌握物理概念呢?现就高中物理教学实践过程谈谈指导学生掌握物理概念的策略.     

Much ado in mechanics

The connection between “dynamical groups” and time-dependent constants of the motion in non-relativistic mechanics is clarified in relation to work done some time ago. The equivalence of certain types of time-dependent systems to time-independent ones is noted.     

Friction at the mesoscale

The organization of structures at the mesoscale is assumed to be the most important mechanism for the majority of friction types. Evidence is provided for the hypothesis that defect organization is fundamental to both tribological and internal friction.     

Strings Have Spin

If a string source is used to replace the conventional point-like source of gravitation in spacetime with torsion, then intrinsic spin arises naturally as an attribute of the string. This spin stems from the structure of the string, and not from internal motions.     

Rolling Friction

Doklady Physics - The dependence of rolling friction on velocity for various contact conditions is discussed. The principal difference between rolling and other types of relative motion (sliding...     

Did nonlinear irreversible thermodynamics revolutionize the classical time conception of physics?

From both physical and epistemological viewpoints, the following theses, which nowadays are often discussed in the literature, are examined: Nonlinear thermodynamics renders it possible to grasp evolutionary physical processes; for thermodynamics it introduces, instead of idealized reversible time, a directed time into physics; thus a science is established that is nearer to reality than classical physics. To analyze these theses, the relation of thermodynamics to dynamical physics is considered. In particular, it is demonstrated that, in classical as well as in modern thermodynamics, irreversibility is introduced via conditions which must be formulated in addition to the dynamical laws. To show the reason for this, the epistemological status of the physical time conception is analyzed, and its character as a physical measurement quantity is established.