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00:00Hi kids! Today we will learn what is lever and its types. So let's start!
00:09Kids, we have already learned that machine is any structure that makes our work easier.
00:18And simple machines are those machines that have a few or no moving parts at all.
00:26Today we will learn about lever which is a simple machine and we use it often in our daily life to make our work easier.
00:37Lever is basically a long stick that you push or pull from one side against a fulcrum in order to move something on the other end of the bar.
00:51In order to lift an object by hand requires force.
00:57Example, to lift this heavy weight by hand you require a lot of muscular strength.
01:04But we can lift this object without applying much muscular force using a lever.
01:12Which is nothing but a rigid bar that moves around a fixed support called fulcrum.
01:21Object to be moved or lifted is placed on one side of the rigid bar and force is applied on the other side of the bar to lift it.
01:35Object can be lifted with much ease compared to lifting the object using muscular force.
01:43A lever essentially has three parts, effort, load and fulcrum.
01:53Effort is a point where you apply force.
01:57Fulcrum is a fixed support and load is a point where you want the force applied to act.
02:07There are three types of levers and we call them as three classes of levers based on the varying positions of effort, load and fulcrum.
02:19Let's learn.
02:22In a first class lever, fulcrum is between the effort and the load.
02:30In a second class lever, load is between the effort and fulcrum.
02:38And in the third class lever, effort is between the fulcrum and the load.
02:45Let's revise.
02:52Load in the center second class and effort in the center third class.
03:00You need to remember this.
03:03Now let's see certain things in our daily life based on these three classes of lever.
03:12Here we have a pair of scissors.
03:18This is the point where you apply force.
03:22So this is effort.
03:24This is the fixed support or fixed point.
03:29This is known as fulcrum.
03:32And this is where the applied force acts on an object.
03:38That is, we apply force here and it cuts the paper here.
03:44So this is the load point.
03:48So what we see here, here fulcrum is between the effort and the load.
03:56So this is an example of first class lever as fulcrum is in the center.
04:04Here we have another object of this kind and it is a pair of pliers.
04:11This is the point where we apply force.
04:14So this is effort and this is the fixed point.
04:18So it's the fulcrum.
04:20And this is where the applied force acts on the object.
04:25So this is load.
04:27So again fulcrum is in the center here.
04:31So this too is a first class lever.
04:35Here is another example, a seesaw.
04:41Here the force is being applied.
04:44This is the fixed support.
04:46And here the force is produced and the buoy is lifted up.
04:52So this point is force.
04:55This is fulcrum and this is load.
04:59Again this is an example of first class lever.
05:03So again fulcrum is in the center here.
05:07This is a hammer.
05:09Let's see how is it based on a lever.
05:13And this is a first class lever.
05:17This is the point where you apply force.
05:20And this is where force is being produced or the load is here.
05:28And this is a support or the fulcrum.
05:33So hammer is a class 1 lever.
05:37Now let's see some more examples.
05:42This is a wheelbarrow.
05:45Now let's try to find out if there is a lever in it and which type.
05:52This is the point where force is being applied.
05:56And this is where the force is being used or the load is supported.
06:03And this is the support or the fulcrum.
06:07So this is a lever as it has fulcrum, it has force and it has load.
06:17And here the load is in the center.
06:20That is in the middle of fulcrum and effort.
06:27And we know when the load is in center it's a second class lever.
06:34So wheelbarrow is an example of second class lever.
06:41Now let's learn more examples.
06:45Here we have a nutcracker.
06:50This is the point where we apply force so this is effort.
06:56This is the fixed part or the fulcrum.
07:01And this is where the load is placed.
07:06Or the force we apply is used here.
07:10So we have effort, load and fulcrum here.
07:15So it's a lever but which type?
07:18So here load is in the center.
07:21And we know where the load is in the center it is a second class lever.
07:27So nutcracker is a second class lever.
07:32Now here we have one more example.
07:36Here we have a fishing rod.
07:39It's a lever.
07:41Let's see how and which type.
07:45The center of the rod is a place where you apply force.
07:51And this end of the rod acts as fulcrum or the support.
07:58And the other end of the rod is the load area.
08:02As it supports the load.
08:05So it has fulcrum, effort and load.
08:09And here effort is in the center.
08:14And we learned in the beginning that third class levers have effort in the center.
08:21So this is an example of third class lever.
08:25Let's have another example.
08:28Here we have a tongue.
08:31It's a lever.
08:33Let's see how and which type.
08:36The center of the tongue is the place where you apply force.
08:42And this end of the tongue acts as fulcrum or the support.
08:47And the other end of the tongue is the load area.
08:51As it supports the load.
08:54So it has fulcrum, effort and load.
08:58And here effort is in the center.
09:02And we learned in the beginning that third class levers have effort in the center.
09:09So this is an example of third class lever.
09:14Let's have a look at another such example.
09:19Here we have a stapler.
09:22We often use it for so many purposes.
09:26It's a lever.
09:28Let's see how and which type.
09:31The center of the stapler is the place where you apply force.
09:37And this end of the stapler acts as fulcrum or the support.
09:42And the other end of the stapler is the load area.
09:47As it supports the load.
09:50So it has fulcrum, effort and load.
09:54And here too effort is in the center.
09:58So this is also an example of third class lever.
10:04Let's revise once again.
10:08Effort in the center is third class lever.
10:12Load in the center is second class lever.
10:16And fulcrum in the center is class one lever.
10:21Ok kids, so today we learned what is lever.
10:27It's types and how we can identify the type of lever.
10:32Now you may go ahead and take a quiz to learn more.
10:36Bye-bye.