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Transcript
00:00hi kids today we will learn about force so let's get started first of all we
00:10need to know that nothing can move unless some force is applied on it trees
00:16sway we run walk move any chair or vehicles move only when some force is
00:24applied to them the trees move when wind or air pushes the trees we can run if we
00:32apply force that is we push ourselves forward we can move a chair by either
00:39applying force to push it or apply force to pull it vehicles move when lots of
00:46force is applied through the engine of the car on the tires of the vehicles to
00:51move that is nothing moves unless some force is applied to it and every force
00:58is either push or pull push it can cause movement away from one pushing it and
01:08pull it can cause movement towards the one pulling it let's see it with
01:14examples closing the door of the refrigerator what force can close the
01:21door we will push the door of the refrigerator to close it opening of
01:28refrigerator what force can open the refrigerator we will pull the door to
01:36open it running a bicycle what force is required to run a bicycle you required
01:44to push the paddles to run a bicycle moving a chair you need to push the
01:51chair away from you or you pull it towards you
01:58running also involves pushing yourself forward kicking a ball kicking a ball
02:05requires you to push the ball hard to move it so kids no matter what is the
02:11movement in every movement of every object either pull or push moves the
02:18object we have seen that everything moves with some force and it's either
02:24push or pull now let's see what force can do force can cause an object to
02:32start moving force can cause object to stop moving and can also cause an object
02:41to change its direction here is your toy car you can push it forward you can
02:47pull it back you can change the direction of movement of your car you
02:52can stop your car we learn that every force is either a push or pull but we
03:00can also categorize force depending on whether a force is resulting from a
03:06contact between two objects or there is no contact between two objects now let's
03:15see what our contact forces contact force is the force in which an object
03:23comes in contact with another object they also direct forces examples pushing
03:31a car pulling a rope opening a door and closing a door kicking a ball running a
03:39bicycle in all these examples forces being applied and there is a contact
03:46between two objects only then the object moves you are not opening the door
03:52without touching it you are not kicking the ball without touching it examples of
04:00contact forces are friction normal force tension buoyancy now let's learn
04:07what are non-contact forces the forces that move objects without coming in
04:16contact with the objects or they are invisible forces that is it is a force
04:22applied by an object to another object which is not in direct contact with it
04:28so they are called invisible forces examples gravity a force that causes a
04:37pencil to fall on the ground is gravity it is the pull of the earth that causes
04:43the pencil to fall on the ground leaves fall from the tree to the ground why
04:50because there is a pull from the earth another example of non-contact forces
04:56magnetic force here is a pin now bringing magnet closer to it the magnet
05:03attracts the pin that is the pin is moved towards the magnet without any
05:09contact between the pin and the magnet so there is an invisible or non-contact
05:17force acting here more examples of non-contact forces are nuclear force
05:25electrostatic force so kids today we learned about forces now you may go
05:33ahead and take a quiz to learn more bye-bye