Coulomb's law of friction

Coulomb's law of friction describes how the force of friction between two surfaces depends on the nature of the surfaces and the force pressing them together. It states that the frictional force is proportional to the normal (perpendicular) force pushing the surfaces together, with a constant called the coefficient of friction that depends on the materials involved. Mathematically, it’s expressed as \( F_{friction} = \mu \times N \), where \( \mu \) is the coefficient of friction and \( N \) is the normal force. Essentially, the harder the surfaces are pressed together, the greater the frictional resistance to sliding.