Give examples to show that friction depends on the nature of two surfaces in contact.

The friction depends on the roughness as well as smoothness of the surface. If the surface is rough, then the surfaces in contact have more interlockings and the thus the friction is more. Thus, the object is not able to move easily due to more friction.

If the surface is smooth, then the surfaces in contact have very less interlockings and the thus the friction is less. Thus, the object is able to move easily due to less friction.