Friction is the force that resist on the solid surfaces , fluid layers and material elements sliding each other . There are five types of frictions eg -Dry Frictions =It resists between two solid surfaces in contact.It is subdivided into static friction. -fluid Friction=It is the friction between layers of visciouse fluids that are moving relative to eachother. -Lubricated Friction=It is the case of fluid friction where a fluid separates two solid surfaces. -Skin friction=It is the component of drag the force resisting the motion of the fluid across the surface of the body.