Where does work collide?

In physics, work is the energy transferred to or from a body when a force acts on it through a distance, equal to the force times the displacement along its line of action and measured in joules. Coriolis, in his 1829 Du calcul de l'effet des machines, gave the quantity its name and its modern definition and tied it to the change in a body's kinetic energy, in what is now called the work-energy theorem; in thermodynamics the same idea returns as the pressure-volume work a system exchanges with its surroundings, kept separate from heat in the first law. Here the referent is a measurable transfer of energy, counted in joules, and not a person's labour, a finished artwork, or a count of computational steps.[1]

Unit

One transfer of energy by a force acting through a distance, in joules

Recovery means

In a reversible or frictionless process the work can be recovered, but friction and other dissipation turn some of it irreversibly into heat

Measured by

Computed as the integral of force over displacement, or force times distance for a constant force, and read in joules

In economics and the study of work, labour is purposeful human activity directed at producing goods and services, the effort people supply, often for pay, that combines with land and capital as a factor of production. Adam Smith's 1776 An Inquiry into the Nature and Causes of the Wealth of Nations made labour the source of a nation's wealth and, through the division of labour, the engine of its productivity, and treated it as the real measure of exchangeable value. The referent is a social and economic activity carried out by people, tallied in hours and wages, and not a physical transfer of energy, a finished creative product, or a measure of algorithmic cost.[2]

Unit

One person's productive effort, tallied in hours worked or the wage it commands

Recovery means

Not applicable

Measured by

Gauged through hours worked, employment counts, wages, and the output produced per hour of labour

In literary theory, aesthetics, and copyright law, a work is a completed creative product, a poem, a novel, a symphony, or a painting, treated as a single identifiable object of authorship distinct from any one printing or performance of it. Wellek and Warren's 1949 Theory of Literature, in its chapter on the mode of existence of a literary work of art, argued that the work is neither the ink on the page nor a reader's passing experience but a structured whole realised through them, and copyright law fixes a parallel idea in its protection of an original work of authorship. The referent is an authored artefact identified by its content and its maker and catalogued by title, and not a transfer of energy, a stint of labour, or a tally of operations.[3]

Unit

One authored creative product, identified by its title, content, and author

Recovery means

Not applicable

Measured by

Identified by bibliographic cataloguing, attribution to an author, and registration as a protected work of authorship

In the analysis of parallel algorithms, the work is the total number of primitive operations a computation performs, the cost it would take on a single processor, stated independently of how many processors actually run it. Blelloch's 1996 Programming parallel algorithms set out the work-and-depth cost model, in which an algorithm is judged by its work together with its depth, the length of its longest chain of dependent operations, so that a good parallel algorithm keeps the work close to that of the best sequential method. The referent is an abstract count of operations, a measure of computational cost, and not energy moved by a force, human labour, or a finished creative product.[4]

Unit

The total count of operations a computation performs, as if run on one processor

Recovery means

Not applicable

Measured by

Counted asymptotically as the number of operations in the computation, usually written as a function of the input size