Friction

FRIK-shun /ˈfrɪkʃən/
nounB2GRESAT
FormalScientific

The resistance that one surface or object encounters when moving over another.

Friction always opposes motion or attempted motion. It can be beneficial (e.g., tires on a road) or detrimental (e.g., wear and tear in machinery).

The story behind the word. "Friction" comes from the Latin "frictio," meaning "a rubbing." This is derived from "fricare," meaning "to rub." The etymology perfectly describes the physical phenomenon: the resistance caused by two surfaces rubbing against each other.

Word relationships

  • resistance: "Resistance" is a broader term for opposition; "friction" is a specific type of resistance between surfaces.
  • drag: "Drag" is resistance encountered by an object moving through a fluid (air or water), a specific type of friction.
  • lubrication: The act of applying a substance to reduce friction.
  • smoothness: A surface quality that minimizes friction.

Commonly confused with

  • Tension: Tension is a pulling force exerted by a string or cable; friction is a resistive force between surfaces.

Word family

  • frictional (adjective): Relating to friction.
  • rub (verb): To move one surface against another.

Collocations

  • static friction
  • kinetic friction
  • rolling friction
  • reduce friction
  • coefficient of friction

Idioms & expressions

  • create friction
  • rub off (related to friction)

Example sentences

  • "Lubricants are used to reduce friction between moving parts in an engine, improving efficiency." Explaining a mechanical principle.
  • "Without friction, it would be impossible to walk, as our feet would simply slide across the ground." From a physics demonstration. (Physics Classroom)

Memory hook

FRICTION causes things to RUB and get FRIGHTENINGLY hot. Rubbing Friction

When not to use

While "friction" can be used metaphorically for conflict (e.g., "friction between colleagues"), ensure the context is clear if you mean the physical force.

Fun facts

  • There are different types of friction, including static (object at rest), kinetic (object in motion), and rolling friction.
  • Friction is essential for many everyday activities, from walking to lighting a match.

Related words

Force, Motion, Work

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