• 3 months ago
Transcript
00:00Hi kids today, we will learn about workforce and energy
00:09So let's start
00:14Let's see, what is work?
00:17To most people work means making food
00:21Doing your schoolwork
00:23cleaning home or washing clothes
00:27Etc. But in science work has a different meaning
00:36Example
00:37When someone is swimming he is using force to push the water
00:43His hands and feet push water back to make him move forward
00:50Both
00:52Pushing strokes and the water move in the backward direction
00:59So the swimmer is working hard to swim
01:04Another example look at this picture a boy is trying to push a heavy box
01:11Across the room his muscles are working hard, but he couldn't push hard enough to move the box
01:19In science, we say that the boy has not done any work
01:24Although he has applied force on the box
01:28But the swimmer has done some work
01:32Because he was successful in forcing the water backward and moving himself forward
01:40Let's have a look at another example
01:43Here
01:46This girl is pushing a small box and she is able to move this box across the room
01:55So she has done some work
01:59Here is another example
02:02Here the boy is pushing against the wall
02:05He is applying a lot of force, but the wall is not going anywhere
02:10So no work has been done because the position of wall does not change here
02:17so the work is set to be done when the force applied on an object is
02:23Able to move the object in the direction in which force is applied
02:31Let's see some more examples
02:34If
02:35You are helping to push a car and the car moves in the direction of the applied force
02:41You are doing work and if the car doesn't move at all
02:46You have not done any work at all. No matter how much force you applied to the car
02:54Let's learn. What is the relation between force and work the more force you use
03:01To move something
03:03The more work you do the harder you push the farther and faster the object will move
03:12Now let's learn what is the relation between work and
03:18energy
03:19We know if we apply force only then some work is done
03:26But to exert force we need energy
03:29Energy so energy produces force and force in turn produces work
03:39Now let's learn about energy
03:43We need energy to apply force to do any work
03:48for example if you want to go up the stairs
03:53You need energy to apply force and climb up the stairs
04:02If you want to ride a bicycle for that too
04:06you need energy to apply force on the paddles and
04:11Run a bicycle
04:13So you need energy to apply any kind of force and then only you can do any work
04:22Now, let's learn. What is the definition of energy in science?
04:30In science we say
04:32Energy is the capacity to do work
04:36You can work less than your parents or anyone who is elder to you
04:43Because they have more energy than you or more capacity to do work than you
04:52so energy means
04:55capacity to do any work
04:59Why do we eat food we eat food to get energy to live run work play
05:06Dance study or practically doing any work
05:11We are using energy
05:13When we are doing anything
05:16if
05:18We come home back after a long
05:21Cycling or playing in the park with our friends. We feel hungry
05:29it's because our energy is used while doing anything and
05:36playing
05:37swimming or any physical activity
05:40consumes our energy
05:44Nothing can happen without energy
05:47Energy
05:49Energy is used in different ways and in different forms by different things
05:56Let's see some examples a torch gets energy
06:00From the battery why the light of a torch goes weak when it uses all the energy
06:07stored in its battery a
06:10car gets energy to run from petrol or
06:15Diesel a car has to be filled with petrol if it has to run
06:21All living things need proper food to obtain energy
06:26to carry out various
06:29activities
06:31Now let's learn forms of energy
06:35There are many forms of energy and all forms of energy are capable of doing some work
06:44a
06:45Special property of energy is that it can be changed from one form to another
06:54We can convert one form of energy into another
06:59by suitable instruments
07:01for example
07:03washing machine
07:05Electrical energy is converted into mechanical energy for washing clothes
07:11We
07:14Ourselves are converting the energy stored in food into mechanical energy
07:21In whatever work we do. We are converting the energy stored in food molecules
07:28That is the chemical energy into
07:32mechanical energy
07:35There are different forms of
07:37energy
07:38Muscular energy heat energy
07:41electrical energy wind energy solar energy chemical energy and
07:48many more
07:50We will learn about different forms of energy in our next assignment
07:55Now you may go ahead and take a quiz to learn more
07:59Bye. Bye