Okay, so there you are. Now that you've set aside this time to learn, let me ask you a question. So when you go on a bicycle, you apply a brake. How does this exactly work?
You press it harder, it stops faster. Now you know your shoes don't last forever, right? yet, you know, they wear out. And even when you buy a new shoe, you turn it around and you look at the grip.
So now, why do you do that? What is this thing that we call a grip? What does it really mean? These are all questions we have, right?
Now, even if you were to think about other things, like, have you seen people... people climbing the chimney. It's called chimney climb.
So you will, you have two walls basically, okay, you have two walls and you push against both of them, you can actually stand there for a while, right? So that person is actually literally stuck between a rock and a hard place but aren't you wondering what exactly keeps that person there, right? Why isn't he falling?
Now as you can see in that picture, that person's not falling in that chimney. Something's holding him up there. Now as you think about this even more, when it's cold, we all love... You know, rub our hands and we feel warm, right? You would have done this as well.
If you were on a vacation when it's really cold, you might have done that. Or something very simple you would have probably surely done. You strike a match, right? From nowhere, there is some heat to create that fire.
Where did this heat come from? You rub your hands, there is some heat. You strike a match, once again you're rubbing the match against that matchstick.
So there is some heat. So all of these actually fall under what we're going to learn today. So now that you've set aside this time, for you and I to explore and have fun with this idea that we are going to call friction and let's see what there is in that. Ah!
What is this friction? So if you want to learn anything at all, forget friction, anything at all, the best way to do it is to jump in with all your energy and learn it by making mistakes, asking questions, going crazy with it, right? That's the best way to learn friction as well.
And the best way to do it is by playing with it like we're going to do now. But before we do that, right, there's one thing though that we really have to talk about. And that is this man called Galileo, right? Now he said something that's so important that without that, anything we learn in friction would not make any sense.
Now for a long, long time, Aristotle said, An object... will come to rest by itself. If you push something, it will come to rest.
You all see this happening, of course. So Aristotle also saw this happening. And he said that.
And the great thing about questioning is that Galileo said, I agree with you. I respect you. You push something, it is coming to a stop in this world.
I see that happening. But look at the planets. Look at the moon.
The moon's been going around us. It's been moving for years and years. It doesn't seem to have come to a stop.
The earth itself is going around the sun. In those times, there was a big question about that. But he... Even then, the moon was going around the earth.
It's not stopping. So, how exactly? If the nature of the object is to come to a rest, Galileo asked, shouldn't the moon also come to a rest? So the great thing comes out of asking and questioning things that have been accepted for a long time.
And then Galileo said, I think, when something moves, until somebody else stops it, it will keep going. Big distinction, right? Till then, what Aristotle said?
If something moves, it will stop by itself. Now, Galileo says... something is stopping somebody else is stopping it so what is all what's in all this for us if you push something you see it's stopping right now what does it mean for you it means that somebody else must be stopping it the object is not stopping by itself and that's all you want to know for this chapter's purpose.
So, now let's begin to play, right? Now that you know that an object that is moving will not stop by itself until and unless somebody externally, an external force as you know, right, is applied on it.