Irregularities present on a surface are often described as surface roughness or texture. These surface textures such as grooves and dimples impart friction, which is the force between two sliding ...

It’s a moonless night. The wind howls outside. A door opens slowly, as if pushed by an invisible hand. “Cre-e-e-a-k.” That sound — a horror movie cliché — is the result of friction. A stealthier ...