本文应用质点系的动量定理求解出3种柔软链条运动，揭示出这3种运动各自的特点，同时显示出动量定理方法的优势在于物理思想凸出、计算过程简洁．本文采用迭代的方法，详细逐步地分析计算出第三种运动的具体特征，并采用主要的运动特征参量来描述链条的逐次衰减振荡，给予了必要的图示、论证和说明，发现了一些规律．另外，本文还提出一个实用的所谓“链状质点系沿切向运动的动力学方程”．

 In this paper, three kinds of soft chain motions are solved by using the momentum theorem of particle system, and their respective characteristics are revealed. At the same time, it is shown that the advantages of the method of momentum theorem lie in the protruding physical thought and the concise calculation process. The specific characteristics of the third motion are analyzed and calculated step by step by iterative method, and the main motion characteristic parameters are used to describe the successive attenuation oscillation of the chain. The necessary diagrams, demonstrations and explanations are given, and some regularity are found. In addition, a practical so-called “dynamic equation of tangential motion of chain particle system” is proposed.