 
 
 
Till now we have been studying contact forces
Till now we have been studying contact forces
Till now we have been studying contact forces
These are the forces in which contact between objects is necessary
These are the forces in which contact between objects is necessary for the force to operate between them
 
Muscular force and force of friction
are the examples of contact forces that we have
that we have discussed previously
But is contact between objects always a necessity
for the the forces to come into play
Let us find it out
Take a bar magnet and place it on the table
What is a bar magnet, well we all
well, we all know what magnets are
Our magnet is an artificial magnet which has this shape
place a iron nail on the same table at some distance away from the bar magnet
 
now move the bar magnet toward the nail like this:
keep moving the magnet slowly closer and closer to the nail
but make sure not to touch the nail
What did you notice
When the bar magnet was sufficiently close to the nail, the nail
takes a leap toward the magnet and sticks to it
What does this tell us
this shows that the magnet attracts the nail and the contact
is not necessary for this attraction
the magnet pulled the nail towards it even though it
was not in contact with the nail
The force that this magnet exerts on the nail is called magnetic force
So contact is not required for the magnetic forces to come into play
We call this force a non-contact force
now if you bring the magnet close to your iron cupboard
you will get the same results
as you move this magnet closer and closer to the iron cupboard
The magnet will attract the towards cupboard itself
and visa-versa
however in this case it is the magnet  which will
shoot out of your hand
are there any other non- contact forces
besides the magnetic force
When you release an object, say a plastic ball
from some height above the ground, it just falls
on the ground, why does it fall towards the ground
This is because of the force that the earth exerts
on it in the downward direction
the earth always pull the objects towards it
The force that the earth exerts on an object
is called gravitational force
This force is attractive in nature
that is it attracts two objects towards each other
When you open a tap water begins to flow downwards
This is because of the gravitational pull on the earth on water
Now i want you to tell me is gravitational force a non-contact force
yes
yes it is, we can clearly see from our examples
The contact is not required between the
earth the other object
we say that the gravitational force is a
non-contact force
in the next video we will see one last example
of a non-contact force
see you there
