mass divergence
41Linear elasticity — Continuum mechanics …
42Mermin–Wagner theorem — In quantum field theory and statistical mechanics, the Mermin–Wagner theorem (also known as Mermin–Wagner–Hohenberg theorem or Coleman theorem) states that continuous symmetries cannot be spontaneously broken at finite temperature in systems with …
43solids, mechanics of — ▪ physics Introduction science concerned with the stressing (stress), deformation (deformation and flow), and failure of solid materials and structures. What, then, is a solid? Any material, fluid or solid, can support normal forces.… …
44Alternate history — This article is about the subgenre in fiction. For other uses, see Alternative history (disambiguation). Speculative Fiction Speculative fiction Portal v · d · e …
45Extinction Crétacé-Tertiaire — Badlands près de Drumheller, Alberta, où l érosion a découvert à l air libre la limite K–T …
46organized labour — Introduction also called trade unionism, association and activities of workers in a trade or industry for the purpose of obtaining or assuring improvements in working conditions through their collective action. Great Britain (United… …
47Mathematical descriptions of physical laws — For worded descriptions and criteria of physical laws, see Physical law. For the nomenclature used see Physical quantity and Defining equation (physics). Physical laws are often summarized by a single equation, or at least a small set of… …
48Quantitative comparative linguistics — is a branch of comparative linguistics that applies mathematical models to the problem of classifying language relatedness. This includes the use of computational phylogenetics and cladistics to define an optimal tree (or network) to represent a… …
49Groundwater flow equation — Used in hydrogeology, the groundwater flow equation is the mathematical relationship which is used to describe the flow of groundwater through an aquifer. The transient flow of groundwater is described by a form of the diffusion equation, similar …
50Extratropical cyclone — Part of the Nature series on Weather   Calendar seasons Spring · Summer Autumn  …
