Exploring Forces:Direction of Forces Video Lecture - Class 8

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the question is everywhere we talk about
not only the magnitude of force that
means how much force is being applied
but we also talk about the direction
like when you are playing football now
the direction towards which you kick the
ball is equally important right so when
we talk about direction as well as
magnitude so forces a physical quantity
that has both magnitude and direction so
what do we mean by magnitude that means
how much force is being applied for
example if you have to move a box now
you have the same box in the first
scenario you are applying small force
that means less amount of force in the
second scenario do you have again the
same box the same person but here the
person is applying more amount of force
so here if the less force is being
applied here more forces thing so that
means in this case magnitude is small
that means each small amount of force is
being applied now for size magnitude so
now you understand what is magnitude but
it also has Direction like in this case
if you see the person is pushing the box
that means he is trying to apply a force
in this direction so if he applies
sufficient force then the box will move
in this direction similarly here also
force is being applied in this direction
so let us look at these examples so here
also you see in this scenario the person
is lifting the box and he is moving in
this case that person is trying to push
the box in this direction in this case
the person is trying to push the box in
this direction so everywhere you have a
particular direction in which the force
is being applied so it is not only
magnitude which is important that is how
much force is being applied that is
important but besides that direction is
equally important now what will happen
if multiple forces are applied on a
board
in the same direction let's suppose you
have this huge box and there is this
person a who is applying a force in this
direction so let us suppose that this
person a is applying a force say F 1 of
10 10 is the magnitude of the force and
Newton is the unit in which force is
measured for example in order to measure
mass we use KZ right when you go to a
shop to buy potatoes you say that I need
10 kgs potato so kg is nothing but the
reference or the unit of measurement so
similarly when you go to buy milk you
talk in terms of liters similarly when
we talk about force we talk in terms of
Newton so let us suppose this person a
applies a force of 10 Newton on this box
now let us suppose that there is another
person who is also pushing the box 2 in
the same direction so he is also trying
to apply a force in this direction and
what is the force that he is applying
let us say the magnitude of the force is
20 Newton so this person B is applying
greater force when compared to person a
now in this case what will be the total
force that is being applied on this box
by a and B so the net force in this case
will be f1 plus f2 so the net force
acting on the Box will be equal to f1
plus f2 so that will be equal to 10 plus
20 that is equal to 30 Newtons so this
is the total force that is acting on
this box so we see that forces applied
in the same direction get added up now
in this case we added both of them
because the both of these are applied in
the same direction now what will happen
if they are applied in opposite
direction so in this case let us see
what happens
again let us suppose this is person a
and he is applying a force in this
direction so he is actually trying to
push the box in this particular
and let us see that f 1 is equal to 10
Newton now this time let us suppose
person B is not on the same side instead
he is on the other side of the box and
he is trying to push the box in this
direction so he is applying a force in
this direction and the magnitude of this
force is 20 Newtons now in this case
what will happen now when e is applying
a force on the Box the box will tend to
move a little bit in this direction but
at the same time somebody else is
applying a force in this direction so so
even though now how do we know how the
Box will move so the box will move as
per the greater force now clearing this
case f1 is a smaller force but f2 is a
greater force so obviously f2 will
dominate and therefore the box will move
finally in this particular direction and
what would be the net force that is
acting on this box so the net force
acting on this box will be equal to f1
minus f2 because they both are in
opposite direction so they both get
compensated so the net force is the
difference between forces applied in
opposite direction that's because
whatever force is being applied in this
direction they get that get compensated
by an equal and opposite force correct
so here F 1 is 10 Newton and F 2 is 20
Newton's which is greater f2 so that
means the box will move in the direction
of f2 f2 is in this direction so the box
will also move in this direction and the
net force would be equal to 10 minus 20
which is equal to minus 10 Newton so
what does this minus sign indicates so
this minus sign indicates that the box
will be moving in this particular
direction so enter net force acting on
the object is 10 Newtons so now you
understand what happens in forces are
applied in the same direction or in
opposite directions thank you please
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