How can we reduce frition to increase speed? How can we increase friction to reduce speed?Relate this question to cars

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.