our daily life, we often use our muscles to pull or push things: we pull up a
glass of milk to get it to our mouth; we push an object to move in particular
direction etc. We come to realize that either a “pull” or “push” is required to
move an object. So, Force is a push
or pull on an object.
uses force to walk, to lift any object, to throw anything, to move any object
from its place etc. In short, force is there in every activity we do. By
applying force we usually bring anything in motion or in rest position but not
always. Example: If we apply force on a wall
it does not move.
application of force in everyday life
pedal a cycle and cycle moves forward.
bullock cart, a cart is being pulled by a bullock.
team pulling the rope in the game of tug of war.
pull to open the door of our room.
has many effects on the objects it is applied to. It can cause many changes to
the object to which force is applied.
Force causes motion
can bring stationary object in motion provided there is no other force
preventing the motion. When we apply force on any stationary object, it starts
moving in the direction of force. A change in object’s position is called
Example: When we push any toy car, it moves.
when force is applied, a stationary object comes in motion or force changes the
position of stationary object.
Force changes the speed
changes the motion of body that is already in motion.
Example: When we push harder to moving toy
car, its speed increases. Similarly we can apply force in opposite direction of
the motion to slow down the speed of the toy car.
we can say that force changes the speed of an object.
Force stops motion
we apply more force in the opposite direction of the motion, an object stops
Example: When we try to hold the ball thrown to us with
force greater than the force with which it is coming, it stops.
we can say that force can also stop a moving object.
Force change the direction
a force is applied at an angle to a moving object, force changes the direction
of the moving object.
game of badminton, when player hit the shuttlecock back to the player on the opposite
side, his force changes the direction of shuttlecock.
moving car changes its direction when force is applied on its steering wheel so
as to turn it.
game of football, player changes the direction of moving football by hitting
the ball by his foot at an angle.
Force changes the shape
we force is applied on an object its shape and size changes.
an inflated balloon is pressed, force applied changes its shape.
we squeeze a plastic water bottle, force applied changes its shape and size.
are many different kinds of force. Some of them are:
brush our teeth, lift our bag, write with our hand, walk to the school, and get
up from our desk. In all these activities we do use our muscles to apply force.
The force applied by our muscles to carry out all our activities is called muscular
applies his muscular force to give shape to his pots.
apply muscular force to lift a box, ride a cycle, swim, walk etc.
applied by a machine is called mechanical force.
applied by bulldozer to move the soil.
applied by digger to dig the earth.
we throw a ball up in the sky, it comes down and when we jump, we come back on
earth. Why this happens? This is the earth which pulls things towards it. That
is why apple drop down on the ground from a tree instead of going into the sky.
The pull of the earth is a kind of force. This force is called gravitational
force. It is this pull of the earth which keeps us and other object on
earth from drifting into space. This force was discovered by Sir. Isaac
magnet is a material that attracts things made of iron, nickel and cobalt.
of magnet is called magnetic force.
we roll down a ball on grassy ground, it gradually slows down and finally
stops. This happens because a force acts between the ball and the ground.
Therefore, frictional force is the force exerted by a surface as an
object moves across it or makes an effort to move across it.
Example: When we slide pencil across the surface of
a desk, then the desk exerts a friction force in the opposite direction of its
motion and pencil slow down and finally stops sliding.
friction slow down or prevent motion, it prevents us from slipping all the
time, enable us to walk without falling, apply break in our vehicles, makes the
movement of vehicle possible on road.
force is greater on rough surfaces such as grassy ground, on woolen clothes and
lesser on smooth and slippery surface.