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00:00hi kids today we will learn more about the force of friction so let's get
00:07started friction is a force that resists motion when two surfaces are in contact
00:15with each other friction occurs when two things rub together let's see it with an
00:23example take a toy car push it on different types of surfaces from rough
00:30to smooth and see and record how far it goes every time first push a car on a
00:39very rough surface like a carpet and see how far the car goes now push it on a
00:47less rough surface like a cardboard and see how far it goes now push it on a
00:55very smooth surface and see how far it goes
01:02result is very clear smoother the surface faster and farther the car goes
01:11this is because the rougher the surface the more the friction it poses or the
01:18opposing force for any movement the smoother the surface the lesser the
01:25friction or the opposing force that is why objects goes very fast and smoothly
01:32on smoother surface because there is no or very less opposing force which is
01:39friction so smooth surface pose less friction and the car goes very far so
01:49the point you need to remember is friction acts against any motion when
01:55two objects are in contact with each other and friction acts in opposite
02:01direction of every movement it is a friction that slows down every movement
02:08and eventually stops it and it is the friction because of which there is a
02:14grip between two surfaces if there would be no friction things would just slip
02:22away there will not be any grip between two objects and this is why whenever we
02:29need more grip we create the surfaces rough so that there is more friction and
02:34more grip and wherever we need two objects to slide past each other we
02:39create lesser friction by making the surfaces of objects very smooth we will
02:46see many examples about it here we have a ball now kick it it will start moving
02:55but eventually it slows down and stops it is because of the friction or the
03:03opposing force which is always there if there would have been no friction and
03:09you kick the ball the ball would be moving indefinitely that is it will
03:16never slow down or stop it happens in space there is no friction and gravity
03:22in space and this is why if something is left in space it remains there forever
03:28moving now let's see some examples where we need friction here a girl is trying
03:38to walk on a road covered with ice and it's very difficult as a road is very
03:44slippery why it is because the ice is very very smooth and posing no friction
03:53that makes a surface slippery here the boy wants to climb the pole so should
04:01the pole be very smooth or rough we know the smoother the surface the lesser the
04:07friction if the pole will be very smooth the pole will not pose friction and the
04:13boy will slip but if the pole will be rough it will pose friction and the boy
04:19will not slip so the pole should be rough so that the boy is able to climb
04:25the pole easily so friction is required here so we saw friction where friction
04:33was required now let's see examples where we do not need friction here the
04:42boy wants to go faster to enjoy the ride so friction should it be less or
04:47more there should be very less friction here is another example here in this
04:57bowling game there should be none or least friction so that the ball goes as
05:03fast as possible because the smoother the surface the lesser the friction or a
05:11opposing the force when there is no opposing force the ball is bound to go
05:17very fast now let's see what is the relationship between friction and the
05:24grip we learned that the smoother the surfaces in contact the lesser the
05:31friction that is the surface will not stay in contact they will slip off that
05:36is there will be no grip and rougher the surfaces in contact the higher the
05:43friction or opposing force that is there will be more grip and the two objects
05:49will have better contact so we learned that friction does not let the two
05:54surfaces in contact to slide past each other and creates grip this is why
06:01surface of tires is made as rough as possible to have more grip on the road
06:08otherwise the tires will skid off or slip off the road the smoother things
06:15are slippery to hold because they pose less friction
06:22here is one more example push a striker on the carom board and see how far it
06:28goes now push a striker on the carpet and see how far it goes the striker goes
06:36much farther on the carom board because there is least friction that is no
06:43opposing force and no grip and the surface of carpet is very rough that is
06:49it will pose a lot of friction or a lot of opposing force for the movement of
06:55striker and there is much more grip between the striker and the carpet so it
07:02doesn't move much so wherever you need more grip and control you need friction
07:09so kids today we learned what is friction now you may go ahead and take a
07:16quiz to learn more bye-bye