Rigid or rigidity may refer to:
Mathematics and physics
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Stiffness
Stiffness is the extent to which an object resists deformation in response to an applied force.
The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is.
Calculations
The stiffness, k, of a b ...
, the property of a solid body to resist deformation, which is sometimes referred to as rigidity
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Structural rigidity
In discrete geometry and mechanics, structural rigidity is a combinatorial theory for predicting the flexibility of ensembles formed by rigid bodies connected by flexible linkages or hinges.
Definitions
Rigidity is the property of a structu ...
, a mathematical theory of the stiffness of ensembles of rigid objects connected by hinges
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Rigidity (electromagnetism), the resistance of a charged particle to deflection by a magnetic field
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Rigidity (mathematics), a property of a collection of mathematical objects (for instance sets or functions)
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Rigid body
In physics, a rigid body (also known as a rigid object) is a solid body in which deformation is zero or so small it can be neglected. The distance between any two given points on a rigid body remains constant in time regardless of external fo ...
, in physics, a simplification of the concept of an object to allow for modelling
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Rigid transformation
In mathematics, a rigid transformation (also called Euclidean transformation or Euclidean isometry) is a geometric transformation of a Euclidean space that preserves the Euclidean distance between every pair of points.
The rigid transformatio ...
, in mathematics, a rigid transformation preserves distances between every pair of points
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Rigidity (chemistry), the tendency of a substance to retain/maintain their shape when subjected to outside force
*(Modulus of)
rigidity or shear modulus (material science), the tendency of a substance to retain/maintain their shape when subjected to outside force
Medicine
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Rigidity (neurology)
Spasticity () is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia. It is also colloquially referred to as an unusual "tightness", stiffness, or "pull" of muscles ...
, an increase in muscle tone leading to a resistance to passive movement throughout the range of motion
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Rigidity (psychology), an obstacle to problem solving which arises from over-dependence on prior experiences
Other uses
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Real rigidity, and
nominal rigidity, the resistance of prices and wages to market changes in macroeconomics
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Ridgid, a brand of tools
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