sliding friction

Sliding friction is the force that opposes the motion of two surfaces sliding past each other. It results from the interactions between the microscopic bumps and irregularities on both surfaces, which momentarily catch on each other as they move. This force depends on the types of materials involved and the roughness of their surfaces, and it always acts to slow down or resist the sliding motion. Sliding friction is essential in controlling movement, allowing us to walk, drive, or write without slipping uncontrollably.