Physicist Richard Feynman wondered what would happen if an S-shaped lawn sprinkler, which rotates as water squirts out, were placed underwater and had its flow direction reversed, so that it sucked water in. Which direction would it rotate? Experiments have given conflicting answers, but now researchers have provided what appears to be a definitive resolution. When sucking water in, the sprinkler reverses its rotational direction, and the motion is unsteady and much slower. The explanation involves the details of fluid flow in the sprinkler geometry.

cross-posted from: https://mander.xyz/post/9079658

Sauce: https://mastodon.social/@gutenberg_org/111845638304911489

Is it possible to determine the percentage of the gravitational force at a specified distance using only the geometry of the planet?

Example: The ISS at ~420km altitude "weighs" about 90% of what it would on the Earth's surface.

Is there an equation using only geometrical values that would give you this info?

cross-posted from: https://slrpnk.net/post/5710029

Institution: Wikiversity
Lecturer: Boud Roukema
Subject: #physics #specialrelativity #generalrelativity
Description: Special relativity and steps towards general relativity is a one-semester Wikiversity course that uses the geometrical approach to understanding special relativity and presents a few elements towards general relativity. The course may be used in a traditional university, within the conditions of the free licensing terms indicated at the bottom of this Wikiversity web page. It may be modified and redistributed according to the same conditions, for example, via the Wikiversity and Wikimedia Commons web sites.

A proposed model unites quantum theory with classical gravity by assuming that states evolve in a probabilistic way, like a game of chance.