啥是悬链线？为什么最稳定？再谈费马的最小作用量原理

Whole-channel inclusion: 妈咪说MommyTalk is an honest teaching channel (title sample + 3 transcripts read: The sampled transcript (video 2) shows in-depth, structured physics explanation despite a news-style hook, consistent with the channel's pattern of genuine science teaching even when framed by current events.); this title passed a strict title check (sonnet) after a labelling pass.

A 10-minute video from 妈咪说MommyTalk: “啥是悬链线？为什么最稳定？再谈费马的最小作用量原理”.

Video by 妈咪说MommyTalk, played through YouTube's embedded player.