用功能原理讨论绳上横波能量问题

推导在一般情况下（不限于小扰动）作用于绳上某一质元两端张力所作功的表达式，导出了绳上某一质元能量与张力所做的功之间的关系，直观地得出行波能量传递是通过张力作功实现的，驻波的能量在波节、波腹之间转移也是张力作功的结果。

DISCUSSION ON THE ENERGY OF THE TRANSVERSE WAVE IN THE STRING WITH WORK-ENERGY THEOREM

The expression of the work done by tension at both ends of a mass element of the string in general is deduced and the relationship between the energy of a mass element of the string and the work done by tension obtained. It shows that the energy transport is finished by work of tension, and that it is the result of the work of tension that the energy of the standing wave changes from the node to the antinode.