Frictionial sliding refers to the movement on a preexisting surface when shear surface exceeds sliding resistance.

Frictional force is function of normal force. Frictional force is independent of the area of contact and independent of material used- weight of the block is dependent. whys is that?

There is roughness to every surface which anchor the surface in the asperities. ifthe block is heavier ore areas will touch and increase how anchored the object is to the surface.

A scaled up pool ball has higher topographical area than our own planet does if pool ball was size of earth.

Table with legs on carpet= contact points sliding along a surface