Friction is the force created when solid surfaces, fluid layers or material elements slide against each other.
Static Friction occurs between surfaces that are not moving over one another.
Rolling Friction occurs between a solid and a surface on which it rolls.
Sliding Friction occurs as one surface rubs against another.
Fluid Friction occurs as an object passes through air or fluid (also called Skin Friction).
Dry Friction is between solid surfaces in contact.
Lubricated Friction is between solid surfaces separated by a lubricant.
Friction as a force produces energy in the form of heat. In the case of fluid friction, the energy produced occurs as heat plus slowing of the moving object.
Fluid friction can be reduced by smoothing and polishing the surface of the moving body, as well as by its aerodynamic design, resulting in increased speed and decreased heat as the object moves through the air or fluid. This concept is used in the design of aerospace re-entry vehicles.
Lubricated friction can be reduced and speed increased by choosing an optimal lubricant such as Teflon material or lightweight oil.
Sliding friction can be reduced and speed increased by placing ball bearings between the opposing surfaces.
Sliding friction can be increased and speed reduced by applying pressure to the opposing surfaces. This principle is applied to the design of automotive disc brakes.
Thus, friction is reduced and speed increased through polishing of surfaces, aerodynamic design and lubricant technology. Friction is increased and speed reduced by roughening of surfaces, use of less viscous lubricants, and boxy, non-aerodynamic design.
reduction of friction is realy easy. just lubricate. if its a machine you could use ball bearings..
to increase friction and reduce speed.. roughen up the surface of the materials. this causes more friction and obviously reduces speed....