virtual work
Virtual Vir"tu*al (?; 135), a. [Cf. F. virtuel. See {Virtue}.] 1. Having the power of acting or of invisible efficacy without the agency of the material or sensible part; potential; energizing. [1913 Webster]

Heat and cold have a virtual transition, without communication of substance. --Bacon. [1913 Webster]

Every kind that lives, Fomented by his virtual power, and warmed. --Milton. [1913 Webster]

2. Being in essence or effect, not in fact; as, the virtual presence of a man in his agent or substitute. [1913 Webster]

A thing has a virtual existence when it has all the conditions necessary to its actual existence. --Fleming. [1913 Webster]

To mask by slight differences in the manners a virtual identity in the substance. --De Quincey. [1913 Webster]

{Principle of virtual velocities} (Mech.), the law that when several forces are in equilibrium, the algebraic sum of their virtual moments is equal to zero.

{Virtual focus} (Opt.), the point from which rays, having been rendered divergent by reflection of refraction, appear to issue; the point at which converging rays would meet if not reflected or refracted before they reach it.

{Virtual image}. (Optics) See under {Image}.

{Virtual moment} (of a force) (Mech.), the product of the intensity of the force multiplied by the virtual velocity of its point of application; -- sometimes called {virtual work}.

{Virtual velocity} (Mech.), a minute hypothetical displacement, assumed in analysis to facilitate the investigation of statical problems. With respect to any given force of a number of forces holding a material system in equilibrium, it is the projection, upon the direction of the force, of a line joining its point of application with a new position of that point indefinitely near to the first, to which the point is conceived to have been moved, without disturbing the equilibrium of the system, or the connections of its parts with each other. Strictly speaking, it is not a velocity but a length.

{Virtual work}. (Mech.) See {Virtual moment}, above. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

### Look at other dictionaries:

• Virtual work — on a system is the work resulting from either virtual forces acting through a real displacement or real forces acting through a virtual displacement. In this discussion, the term displacement may refer to a translation or a rotation, and the term …   Wikipedia

• Virtual work — Virtual Vir tu*al (?; 135), a. [Cf. F. virtuel. See {Virtue}.] 1. Having the power of acting or of invisible efficacy without the agency of the material or sensible part; potential; energizing. [1913 Webster] Heat and cold have a virtual… …   The Collaborative International Dictionary of English

• virtual work — virtualusis darbas statusas T sritis fizika atitikmenys: angl. virtual work vok. virtuelle Arbeit, f rus. виртуальная работа, f; возможная работа, f pranc. travail virtuel, m …   Fizikos terminų žodynas

• virtual work — /ˈvɜtʃuəl wɜk/ (say verchoohuhl werk) noun (in physics) the work done by a set of forces acting on a body, when the body is imagined to undergo a small displacement. The principle is used to calculate the equilibrium position of a body, or system …   Australian English dictionary

• principle of virtual work — virtualiojo darbo principas statusas T sritis fizika atitikmenys: angl. principle of virtual work vok. Prinzip der virtuellen Arbeit, n rus. принцип виртуальной работы, m pranc. principe du travail virtuel, m …   Fizikos terminų žodynas

• principle of virtual work — Mech. the principle that the total work done by all forces on a system in static equilibrium is zero for a set of infinitesimally small displacements. * * * …   Universalium

• principle of virtual work — Mech. the principle that the total work done by all forces on a system in static equilibrium is zero for a set of infinitesimally small displacements …   Useful english dictionary

• Virtual assistance — (or VA) is the professional service of remote administrative office and other specialized support by an Independent contractor called a virtual assistant who works with clients in an ongoing, collaborative professional relationship.Job… …   Wikipedia

• Virtual — Vir tu*al (?; 135), a. [Cf. F. virtuel. See {Virtue}.] 1. Having the power of acting or of invisible efficacy without the agency of the material or sensible part; potential; energizing. [1913 Webster] Heat and cold have a virtual transition,… …   The Collaborative International Dictionary of English

• Virtual focus — Virtual Vir tu*al (?; 135), a. [Cf. F. virtuel. See {Virtue}.] 1. Having the power of acting or of invisible efficacy without the agency of the material or sensible part; potential; energizing. [1913 Webster] Heat and cold have a virtual… …   The Collaborative International Dictionary of English