Harbor (disambiguation)

A harbor is a place where ships may shelter from the weather or are stored.

Other uses include:

Glossary of professional wrestling terms

Professional wrestling has accrued a considerable nomenclature through its long existence. Much of it stems from the industry's origins in the days of carnivals and circuses, and the slang itself is often referred to as "carny talk." In the past, wrestlers used such terms in the presence of fans so as not to reveal the worked nature of the business. In recent years, widespread discussion on the Internet has popularized these terms. Many of the terms refer to the financial aspects of pro wrestling in addition to performance-related terms.

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References

Work (physics)

In physics, a force is said to do work if, when acting on a body, there is a displacement of the point of application in the direction of the force. For example, when a ball is held above the ground and then dropped, the work done on the ball as it falls is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement).

The term work was introduced in 1826 by the French mathematician Gaspard-Gustave Coriolis as "weight lifted through a height", which is based on the use of early steam engines to lift buckets of water out of flooded ore mines. The SI unit of work is the newton-metre or joule (J).

Units

The SI unit of work is the joule (J), which is defined as the work expended by a force of one newton through a distance of one metre.

The dimensionally equivalent newton-metre (N⋅m) is sometimes used as the measuring unit for work, but this can be confused with the unit newton-metre, which is the measurement unit of torque. Usage of N⋅m is discouraged by the SI authority, since it can lead to confusion as to whether the quantity expressed in newton metres is a torque measurement, or a measurement of energy.

Work (electrical)

Electrical work is the work done on a charged particle by an electric field. The equation for 'electrical' work is equivalent to that of 'mechanical' work:

where

The electrical work per unit of charge, when moving a negligible test charge between two points, is defined as the voltage between those points.

Overview

Qualitative overview

Particles that are free to move, if positively charged, normally tend towards regions of lower voltage (net negative charge), while if negatively charged they tend to shift towards regions of higher voltage (net positive charge).

However, any movement of a positive charge into a region of higher voltage requires external work to be done against the field of the electric force, work equal to that electric field would do in moving that positive charge the same distance in the opposite direction. Similarly, it requires positive external work to transfer a negatively charged particle from a region of higher voltage to a region of lower voltage.

The electric force is a conservative force: work done by a static electric field is independent of the path taken by the charge. There is no change in the voltage (electric potential) around any closed path; when returning to the starting point in a closed path, the net of the external work done is zero. The same holds for electric fields.