Where does mass collide?

The scalar that fixes how much a body resists being accelerated, and, separately, how strongly it gravitates. Newton opened the Principia in 1687 by defining quantity of matter as density times volume and then used it in both roles; that inertial and gravitational mass are the same number was an observed coincidence until Einstein made it a principle. Einstein's 1905 note added the third face: a body's inertia depends on its energy content, so mass and energy are one conserved quantity in two units. Jammer's history traces how a single word came to carry all three ideas. Mass here is measured in kilograms, is additive for ordinary bodies, and is a property of one object, not a crowd.[1][2][3]

Unit

A body, or a bound system of bodies

Recovery means

Not applicable, mass is conserved in ordinary processes; the question is which mass, inertial or gravitational, and in which frame

Measured by

Kilograms; balance against a standard, or acceleration under a known force

A large collection of people who are anonymous to one another, heterogeneous in origin, unorganised, and attending to the same thing without interacting, the audience of a film, the readership of a newspaper. Blumer fixed the definition in 1946 by contrasting the mass with the crowd, which interacts, and the public, which argues. Kornhauser's 1959 theory of mass society made the condition a political danger: people without intermediate groups between themselves and the state are available for mobilisation by elites and by demagogues alike. Lasswell's 1948 formula of who says what to whom in which channel with what effect gave mass communication its research agenda, and McQuail's textbook is the standard synthesis of how the mass audience was theorised, measured and then, with digital media, partly dissolved. The word here describes the receivers, and the description is not a compliment.[4][5][6]

Unit

A population attending to a common medium

Recovery means

Not applicable, the criterion is whether intermediate groups exist and whether the audience fragments

Measured by

Audience size and reach; survey measures of group membership; content analysis of what is transmitted

The strategy of producing one standard offer for the whole market and pulling demand toward it with volume advertising, defined by what it is not. Smith fixed the contrast in 1956: product differentiation bends demand to the supplier's product, market segmentation bends the product to the demands of identifiable sub-markets, and mass marketing is the undifferentiated baseline both improve on. Pine's 1993 book announced its end: flexible production could deliver individually tailored goods at mass-production cost, and Gilmore and Pine in 1997 sorted the ways of doing so into four approaches by whether the product or its representation changes. In marketing the mass is a market, and treating it as one has been out of fashion for seventy years.[7][8][9]

Unit

A market, and the firm's choice of how many offers to make to it

Recovery means

Not applicable, the criterion is fit between offer and segment, at what cost

Measured by

Market share and volume; number of segments served; cost per unit under customisation