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Friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction:
Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into static friction (“stiction”) between non-moving surfaces, and kinetic friction between moving surfaces. With the exception of atomic or molecular friction, dry friction generally arises from the interaction of surface features, known as asperities
Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other.Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces.Skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body.
Internal friction is the force resisting motion between the elements making up a solid material while it undergoes deformation.When surfaces in contact move relative to each other, the friction between the two surfaces converts kinetic energy into thermal energy (that is, it converts work to heat). This property can have dramatic consequences, as illustrated by the use of friction created by rubbing pieces of wood together to start a fire. Kinetic energy is converted to thermal energy whenever motion with friction occurs, for example when a viscous fluid is stirred. Another important consequence of many types of friction can be wear, which may lead to performance degradation or damage to components. Friction is a component of the science of tribology.
Friction is desirable and important in supplying traction to facilitate motion on land. Most land vehicles rely on friction for acceleration, deceleration and changing direction. Sudden reductions in traction can cause loss of control and accidents.
Friction is not itself a fundamental force. Dry friction arises from a combination of inter-surface adhesion, surface roughness, surface deformation, and surface contamination. The complexity of these interactions makes the calculation of friction from first principles impractical and necessitates the use of empirical methods for analysis and the development of theory.
Friction is a non-conservative force – work done against friction is path dependent. In the presence of friction, some kinetic energy is always transformed to thermal energy, so mechanical energy is not conserved.
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Fraction (noun)
A part of a whole, especially a comparatively small part.
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Fraction (noun)
A ratio of two numbers, the numerator and the denominator, usually written one above the other and separated by a horizontal bar.
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Fraction (noun)
A component of a mixture, separated by fractionation.
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Fraction (noun)
In a host.
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Fraction (noun)
A small amount.
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Fraction (noun)
The act of breaking, or state of being broken, especially by violence.
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Fraction (verb)
To divide or break into fractions.
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Friction (noun)
The rubbing of one object or surface against another.
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Friction (noun)
A force that resists the relative motion or tendency to such motion of two bodies in contact.
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Friction (noun)
Massage of the body to restore circulation.
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Friction (noun)
Conflict, as between persons having dissimilar ideas or interests; clash.
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Friction (noun)
the resistance that one surface or object encounters when moving over another
“a lubrication system which reduces friction”
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Friction (noun)
the action of one surface or object rubbing against another
“the friction of braking”
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Friction (noun)
conflict or animosity caused by a clash of wills, temperaments, or opinions
“a considerable amount of friction between father and son”