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Perpetual motion is the motion of bodies that continues forever in an unperturbed system. A perpetual motion machine is a hypothetical machine that can do work infinitely without an external energy source. This kind of machine is impossible, since its existence would violate the first and/or second laws of thermodynamics. [2] [3] [4] [5]
歷史上最著名的第一類永動機是 法國人 亨內考 在 十三世紀 提出的「魔輪」，魔輪通過安放在轉輪上一系列可動的 懸臂 實現永動，向下行方向的懸臂在重力作用下會向下落下，遠離轉輪中心，使得下行方向力矩加大，而上行方向的懸臂在重力作用下靠近轉輪中心，力矩減小，力矩的不平衡驅動魔輪的轉動。 十五世紀 ，學者 達文西 也曾經設計一個相同原理的類似裝置，1667年曾有人將達文西的設計付諸實踐，製造一部直徑5米的龐大機械，但是這些裝置經過試驗均以失敗告終。 除了利用力矩變化的魔輪，還有利用浮力、水力等原理的永動機問世，但經過試驗，已確認這些永動機方案失敗或僅只是騙局，無一成功。
Perpetual motion, the action of a device that, once set in motion, would continue in motion forever, with no additional energy required to maintain it. Such devices are impossible on grounds stated by the first and second laws of thermodynamics. Learn more
- The Editors of Encyclopaedia Britannica
2023年8月23日 · And what about a perpetual motion machine of the third kind, with zero friction and in a perfect vacuum without producing any usable energy? It won’t work either; atoms in motion dissipate their energy over time. Superconducting materials, with zero resistance
Perpetual motion machines are devices that are purported to create useful work for “nothing” by violating some physical principle. Generally they are divided into two types, perpetual motion machines of the first and second kinds.
Perpetual Motion: The Holy Grail of Mechanical Engineering | UT Austin Executive Education. Imagine a device so efficient that, once activated, it would work until the eventual heat death of the universe. This is the idea behind perpetual motion, a concept that has fascinated and confounded mechanical engineers for hundreds of years.
Orffyreus' Mersseburgische Perpetuum Mobile. Boyle's perpetual motion scheme. There are two types of perpetual motion machines: Perpetual motion machines of the first kind are those devices that violate the first law of thermodynamics, the principle of conservation of energy, creating energy out of nothing.
