Types of Friction - Friction, Class 8 Science Video Lecture

types of friction
introduction we do activities like
walking running and playing and in all
these activities fiction play an
important role you must have seen people
skiing on snow an interesting sport that
needs balancing and knowledge of
frictional force do you know that
frictional forces can be classified
based on its features let us find out
the various types of frictional force
objectives at the end of this lesson you
will be able to describe the types of
friction discuss advantages and
disadvantages of friction illustrate the
way to reduce or increase the friction
friction can be classified into four
types static friction sliding friction
rolling friction and fluid friction the
ball on ground is at rest at this point
static friction is acting on it the
frictional force that exists between the
two surfaces so long as they are
relatively at rest when an external
force acts is called static friction
there is no actual movement of the body
in static friction in static friction
force of static friction is equal to the
applied force static friction ends with
the beginning of sliding of the object
and Trust when we push the ball it
starts moving the frictional force
present when one body moves slowly or
slides over another body is known as
sliding friction once our body slides
the sliding friction is reduced a little
it is less than the static friction in
sliding friction the force of sliding
friction is equal to the constant pull
force you must have seen attaches and
other pieces of luggage fitted with
rollers if when a child can pull such
pieces of luggage
why is it so let us find out the rollers
reduce friction and roll on the objects
on rollers it is always easier to roll
than to slide a body over another that
is the reason it is convenient to pull
the luggages fitted with rollers the
force of friction between the rollers on
a body and the surface is called the
rolling friction rolling friction is
much less than the sliding friction
since the rolling friction is smaller
than the sliding friction sliding is
replaced in most machines by rolling by
the use of ball bearings common examples
are the use of ball bearings between
hubs and the axles of ceiling fans and
bicycles