# Friction

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).

- Friction

500 related topics

## Viscosity

Measure of its resistance to deformation at a given rate.

Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion.

## Mechanical energy

Sum of potential energy and kinetic energy.

In all real systems, however, nonconservative forces, such as frictional forces, will be present, but if they are of negligible magnitude, the mechanical energy changes little and its conservation is a useful approximation.

## Kinetic energy

The first to publish the relation for kinetic energy . In relativistic mechanics, this is a good approximation only when v is much less than the speed of light.

On a level surface, this speed can be maintained without further work, except to overcome air resistance and friction.

## Polytetrafluoroethylene

Synthetic fluoropolymer of tetrafluoroethylene that has numerous applications.

PTFE has one of the lowest coefficients of friction of any solid.

## Stiction

Stiction is the static friction that needs to be overcome to enable relative motion of stationary objects in contact.

## Conservative force

Force with the property that the total work done in moving a particle between two points is independent of the path taken.

Gravitational force is an example of a conservative force, while frictional force is an example of a non-conservative force.

## Vibration

Mechanical phenomenon whereby oscillations occur about an equilibrium point.

Such vibrations could be caused by imbalances in the rotating parts, uneven friction, or the meshing of gear teeth.

## Charles-Augustin de Coulomb

French officer, engineer, and physicist.

He also did important work on friction.

## Brake

Mechanical device that inhibits motion by absorbing energy from a moving system.

Most brakes commonly use friction between two surfaces pressed together to convert the kinetic energy of the moving object into heat, though other methods of energy conversion may be employed.

## Tribology

Science and engineering of interacting surfaces in relative motion.

It includes the study and application of the principles of friction, lubrication and wear.

Hyperleap, 2022