Kinetic friction, also known as sliding friction, is the force that resists the motion of an object as it slides across a surface.
Kinetic friction only occurs when the object is already in motion, while static friction occurs when the object is at rest and trying to be set in motion. Kinetic friction is typically lower than static friction.
The magnitude of kinetic friction is affected by the coefficient of friction between the two surfaces, the normal force acting on the object, and the roughness of the surfaces.
The coefficient of kinetic friction is determined by dividing the force of kinetic friction by the normal force acting on the object.
Kinetic friction can be reduced by using lubricants between the surfaces, smoothing out rough surfaces, or reducing the weight or force pressing the surfaces together.