set+equal+to
131Steam whistle — A steam whistle is a device used to produce sound with the aid of live steam. Unlike a horn, the sounding mechanism of a whistle contains no moving parts (compare to train horn).The whistle consists of the following main parts, as seen on the… …
132Kepler problem in general relativity — The Kepler problem in general relativity involves solving for the motion of two spherical bodies interacting with one another by gravitation, as described by the theory of general relativity.Typically, and in this article, one body is assumed to… …
