Concentric

# Concentric

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Encyclopedia

Concentric object
Object (philosophy)
An object in philosophy is a technical term often used in contrast to the term subject. Consciousness is a state of cognition that includes the subject, which can never be doubted as only it can be the one who doubts, and some object or objects that may or may not have real existence without...

s share the same center, axis or origin
Origin (mathematics)
In mathematics, the origin of a Euclidean space is a special point, usually denoted by the letter O, used as a fixed point of reference for the geometry of the surrounding space. In a Cartesian coordinate system, the origin is the point where the axes of the system intersect...

with one inside the other. Circle
Circle
A circle is a simple shape of Euclidean geometry consisting of those points in a plane that are a given distance from a given point, the centre. The distance between any of the points and the centre is called the radius....

s, tubes, cylindrical shafts, disk
Disk (mathematics)
In geometry, a disk is the region in a plane bounded by a circle.A disk is said to be closed or open according to whether or not it contains the circle that constitutes its boundary...

s, and sphere
Sphere
A sphere is a perfectly round geometrical object in three-dimensional space, such as the shape of a round ball. Like a circle in two dimensions, a perfect sphere is completely symmetrical around its center, with all points on the surface lying the same distance r from the center point...

s may be concentric to one another. Concentric objects generally have different radii, as concentric objects with the same radius are equal.

One of the most familiar examples of concentric circles are the evenly spaced circles of a target used in target archery
Target archery
Modern competitive archery is governed by the World Archery Federation, abbreviated WA . Olympic rules are derived from WA rules. WA is the International Olympic Committee's recognized governing body for all of archery.Currently 142 nations are represented by WA archery governing bodies...

or firearms, and accordingly any concentric design may be called a "target" or a "bullseye
Bullseye (target)
The bullseye, or bull's-eye, is the centre of a target , and by extension the name given to any shot that hits the bullseye...

" (after the center).

## Examples of concentric phenomena

Concentric
Coaxial cable
Coaxial cable, or coax, has an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis...

cable
Cable
A cable is two or more wires running side by side and bonded, twisted or braided together to form a single assembly. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry...

is a cable type used in TN-C-S earthing systems where the combined neutral and earth core completely surrounds the live core(s). This minimizes the risk of completely cutting through the combined neutral and earth without first completely cutting through the live cores.

Concentric muscles contractions are those in which the muscle shortens.

• Coaxial
Coaxial
In geometry, coaxial means that two or more forms share a common axis; it is the three-dimensional linear analogue of concentric.Coaxial cable, as a common example, has a wire conductor in the centre a circumferential outer conductor and an insulating medium called the dielectric separating...

• Concentric castle
Concentric castle
A concentric castle is a castle with two or more concentric curtain walls, such that the outer wall is lower than the inner and can be defended from it. The word concentric does not imply that these castles were circular; in fact if taken too literally the term "concentric" is quite misleading...

• Eccentricity
Eccentricity (mathematics)
In mathematics, the eccentricity, denoted e or \varepsilon, is a parameter associated with every conic section. It can be thought of as a measure of how much the conic section deviates from being circular.In particular,...

• Twinax