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对变质量问题的实验研究王晓耕,郝利(承德石油高等专科学校,067000)在大学物理教学和习题中常遇到变质量问题,我们在气垫导轨的滑块上增加了载沙槽装置,在导轨上端悬挂一沙漏斗,当载沙槽、滑块组成的系统在外力作用下沿导轨运动时,漏斗中的沙子匀速地落在运... 相似文献
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变质量问题的教学之浅见 总被引:1,自引:1,他引:0
本文阐明了变质量物体的运动这一内容在理论力学课的教学中的重要地位,提出了学生难以理解和容易混淆的几个问题,介绍了作者在教学实践中的几点做法。 相似文献
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定滑轮模型是物理中常见的模型之一,中学物理中一般不要求考虑滑轮的质量,而普通物理部分,在学生学习过刚体转动的有关知识后,可以逐步考虑滑轮质量对运动的影响.如文献[1~3]就例举到"绳跨过有质量的定滑轮"问题.但在计及定滑轮的质量时,上述文献认为,滑轮两侧的绳张力大小不同,差值提供滑轮转动的力矩.笔者认为下此结论似乎过于匆忙,张力应是物体内部各部分由于形变而产生的内力,绳与滑轮是两个物体,它们间并不能形成张力,两者之间只有因挤压形变产生的在滑轮法向的弹力和沿切向的静摩擦力.显然,法向的弹力通过滑轮的转动点,是不能够产生力矩的,那么,只有静摩擦力才是滑轮的力矩的真正产生者. 相似文献
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The differential equations of motion of a relativistic variable mass system are given.By using the invariance of the differential equations under the infinitesimal transformations of groups,the determining equations and the restriction equations of the Lie symmetries of a relativistic variable mass system are built,and the structure equation and the conserved quantity of the Lie symmetries are obtained.Then the inverse problem of the Lie symmetries is studied.The corresponding Lie symmetries are found according to a known conserved quantity.An example is given to illustrate the application of the result. 相似文献
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Mei symmetry and Mei conserved quantity of Appell equations for a variable mass holonomic system of relative motion 下载免费PDF全文
Mei symmetry and Mei conserved quantity of Appell equations for a variable mass holonomic system of relative motion are studied.The definition and criterion of the Mei symmetry of Appell equations for a variable mass holonomic system of relative motion under the infinitesimal transformations of groups are given.The structural equation of Mei symmetry of Appell equations and the expression of Mei conserved quantity deduced directly from Mei symmetry for a variable mass holonomic system of relative motion are gained.Finally,an example is given to illustrate the application of the results. 相似文献
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Lie symmetry and the generalized Hojman conserved quantity of Nielsen equations for a variable mass holonomic system of relative motion 下载免费PDF全文
Lie symmetry and the generalized Hojman conserved quantity of Nielsen equations for a variable mass holonomic system of relative motion are studied. The determining equation of Lie symmetry of Nielsen equations for a variable mass holonomic system of relative motion under the infinitesimal transformations of groups is given. The expression of generalized Hojman conserved quantity deduced directly from Lie symmetry for a variable mass holonomic system of relative motion is obtained. An example is given to illustrate the application of the results. 相似文献
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Noether‘s theory of a rotational relativistic variable mass system is studied.Firstly,Jourdain‘s principle of the rotational relativistic variable mass system is given.Secondly,on the basis of the invariance of the Jourdain‘s principle under the infinitesimal transformations of groups,Noether‘s theorem and its inverse theorem of the rotational relativistic variable mass system are presented.Finally,an example is given to illustrate the application of the result. 相似文献
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The symmetry of Lagrangians of a holonomic variable mass system is studied.Firstly,the differential equations of motion of the system are established.Secondly,the definition and the criterion of the symmetry of the system are presented.Thirdly,the conditions under which there exists a conserved quantity deduced by the symmetry are obtained.The form of the conserved quantity is the same as that of the constant mass Lagrange system.Finally,an example is shown to illustrate the application of the result. 相似文献
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从Мещерский方程出发,建立变质量力学系统的高阶D'Alembert-Lagrange原理,导出变质量完整力学系统的各类高阶运动微分方程.结果表明,它们扩充和优化了完整力学的相关理论.
关键词:
变质量完整力学系统
高阶力变率
高阶D'Alembert-Lagrange原理
高阶运动微分方程 相似文献