Friction is the force that resists the movement always. This is always the resistance of relative motion between two or more objects or surfaces. This can also be occurring between two gaseous layers or two liquid layers. There are many types of friction and each type of friction occurs at certain times.
Laws of Friction –
There are five laws of friction. They are as follows-
Dry Friction –
Dry friction is the most popular type of friction every one is familiar about. Dry friction is the friction that resists the relative motion between two solid objects that are in contact. Dry friction if further divided into two types of friction. They are
- Static Friction
- Kinetic Friction
Static Friction is the friction that is created between two stationary objects.
Kinetic friction is the friction that is created between two moving objects.
Static friction is higher than the Kinetic friction as the creation of movement of a static body is more difficult than the body that that is already in movement. The surfaces hold together more firmly in the static friction than in the Kinetic friction.
Fluid Friction –
Fluid friction can be clearly stated as the friction between two viscous fluid layers that are moving relative to each other. The two fluid layers may be liquid & liquid, liquid & gas or gas & gas. Fluid friction is less than dry friction.
Lubricated Friction –
We do lubrication to reduce the friction between two solid surfaces. One best example of the lubricated friction is that the lubrication provided in the ball bearings. The ball bearings and the metal surrounding it has a continuous contact and friction needs to be reduced as much as possible to increase the efficiency and to reduce the losses. This type of friction is known as Lubricated Friction.
Skin Friction –
Skin Friction is a drag component in which the force resists the motion of the fluid. This friction can be produced only at the motion of the fluid and at the place fluid moves across the surface of the body. Laminar flow is defined as the movement of fluid layers in parallel paths which is almost very rare in nature. When the fluid flows, we need to consider many frictions and skin friction plays a major role for producing Skin Friction Drag. The turbulent flow is defined as the zig zag or irregular flow of fluid layers which is very common. These can be seen in flowing rivers, moving water and more. Skin friction does not play an important role in the turbulent flow as Skin Drag Friction produced is low.
Internal Friction –
Internal Friction is a force that resists motion between two solid surfaces. The main difference between the internal friction and the dry friction is that the dry friction consists of two objects or surfaces which resists the movement and the internal friction is the friction produced while making a solid material that is going to be deformed.
