关于荡秋千的功能问题讨论

有的文献认为秋千越荡越高是由于秋千踏板对人脚的作用力做功而使系统有能量输入，本文提出不同的看法，并从力学原理、能量转换的角度全面分析了秋千越荡越高的原因。

Why is a swing apt to swing higher? Some papers assume that's because the effort a swing itself towards a person's feet works and then develops energy to the system. However， I hold different opinions. The following dissertation analyses this swing phenomenon based on Mechanics Principle as welll as Energy Diversion.