Have you ever thought that there is
something which pulls you back while
running? Probably NOT! You might
think that when you run, nobody
seems to pull you!! Friction is the
answer to this question. Senior
students
would
know
what
is
friction. For our young readers, Friction is
the force resisting the relative motion of solid
surfaces, fluid layers, and material elements
sliding against each other, which basically means that it is a force which
resists motion due to the interlocking of minute(tiny) irregularities on
surfaces of objects (as shown). If we don’t run on a rough surface like
concrete or running track, and on a smooth surface like glass, marble
etc., we would slip as there would be no interlocking and we would keep
on skidding…… So we come to this conclusion that this force actually pulls
us back while running. Friction is a force, therefore it is part of Physics
and part of Science. Thus, scientific reasoning of friction is necessary to
go along with this article. Believe us, it won’t be boring……. :-)
Firstly, there are two types of friction, Static and Kinetic Friction.
1. Static friction is friction between two or more solid objects that are
not moving relative to each other. For example, static friction can
prevent an object from sliding down a sloped surface. The coefficient
of static friction is usually higher than the coefficient of kinetic
friction.
2. Kinetic friction occurs when two objects are moving relative to
each other and rub together (like a sledge on the ground). The
coefficient of kinetic friction is usually less than the coefficient of
static friction for the same materials.