Path: ...!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: Luigi Fortunati Newsgroups: sci.physics.research Subject: The Elevator in Free Fall Date: Thu, 19 Dec 2024 22:51:17 PST Organization: A noiseless patient Spider Lines: 18 Approved: Jonathan Thornburg [remove -color to reply]" Reply-To: fortunati.luigi@gmail.com X-Trace: individual.net oM0p7dGqVIm3Qn7a0PM7UwDdGFtvro3WXNIxYpE/bB5FlAQz/Av3PTKDNl Cancel-Lock: sha1:P6m8zU8rfS1fdarc6JK2zUnVGP8= sha256:DfafINuDQsKUfkocejsGlqi7eKGYByOu8PlZ2W1J1oY= X-Forwarded-Encrypted: i=2; AJvYcCXH9zTP0DAwjHzGrMwR+SoJI1iHEKfPnnBtNHrtdAqAbgcUw1bIT5j5DOBfyYUZbtGzKqVaWj2NtqfSvjQPYw==@gmail.com X-ICQ: 1931503972 X-Auth-Sender: U2FsdGVkX1+q59z2Sn8Oif678O6stiq2y5sdtRU9lKpoZlBT1i5ABa1vuaWdozFt Bytes: 1922 The cables break and the elevator goes into free fall. Newton told us that the elevator accelerates and, therefore, there is a force that makes it accelerate. Then Einstein came along and told us that this is not true and that there is no force that accelerates the elevator in free fall. But if there is no force that accelerates the elevator, it means that the elevator does not accelerate. And if it does not accelerate, then it moves with uniform speed. But speed is not absolute: it is relative. And so I ask: is there any reference system with respect to which its speed is uniform? This is for Newton's second law: force that accelerates mass. Instead, for the first law, Einstein says that a body in the elevator in free fall is at rest with respect to the elevator itself. So, why does a body placed below the center of gravity of a free-falling elevator accelerate downwards, and if it is above the center of gravity, it accelerates upwards? Luigi Fortunati