Add two more 30cm-long characters.
Then it's 60cm.
A person weighing 50 kilograms carries 100 kilograms on his back.
Then I'll weigh 150kg.
It adds 100km speed to my car running at 100 km/h.
Then it'll be 200 kilometers.
And you'll be fined for speeding.
For us, this addition is as natural as pouring sauce into sweet and sour pork.
For scientists in the 17th century, this was the same.
Oh, I'm not saying I ate sweet and sour pork with sauce, but I'm saying that's the addition.
At that time, a representative concept that describes the natural world,
Length, mass, speed, temperature, etc. had only size.
So because numbers alone can represent that size, we can just add it as we did earlier.
But the father of modern science,
Isaac Newton brings a strange concept.
It's force.
Even then, it wasn't without the concept of force.
What do you think force is?
What comes to mind when you think of strength?
"Wow, you're strong.'
What do you mean?
So, "You're strong." "You're really strong."
"Should I put my eyes down?"
force makes the rock move and my eyes move.
In other words, force is an object move.
To be exact, it changes the motion and shape of an object.
Scientists in the 17th century had this kind of concept.
Force changes an object. To cause to move.
This much.
This was a time when, like the renaissance of science, there was a growing theory among scientists that the Earth was moving due to the activities of Copernicus, Galilei, and Kepler.
But so far, most people believed in the theory that the Earth is the center of the world and the celestial body moves around the Earth.
So scientists have never dared to imagine that, even if they would accept the theory of geomorphism, the principle of celestial motion and the principle of earth object movement would be the same.
This is how scary it is.
When everyone says yes, no?
It's only in TV commercials.
But sometimes there are people who don't. We call them Dokgodas.
Newton was one of those Dokgo-dai.
Newton was raised in a bitter conflict with his new father after his father passed away before he was born.
There is also a theory that he hated his stepfather so much that he threatened and verbally abused him to burn the house and was very happy when he died.
Maybe that's why Newton didn't trust others very well.
This personality may have been difficult to make friends with, but it can be a great quality for a scientist.
Newton did not believe when everyone believed that celestial objects were different from terrestrial objects.
So I started to look for the same principle that the two worlds work.
"The planet moves in an elliptical orbit around the sun," said Tico Brahe and Kepler.
There was a fact that proved by actual observation.
If Newton defines the force that causes the planet to move in an elliptical orbit, If the force shows that it works the same for the movement of our terrestrial objects,
it proves that the principles of heaven and earth movement are the same.
Newton did this difficult thing.
It defines universal gravitation, a force that works between two objects that are so famous, separated objects.
But Newton had a problem.
Now we need to explain how things move by force.
There is a lot of force at the same time in the movement of an object.
Gravity, friction, shock.
But because the moving path of an object is one, we had to simplify these different forces into one.
Which means we have to combine our forces into one.
Working together in society is a simple thing to say.
Mathematically, it was difficult.
Because, as we said at the beginning, we didn't do it naturally as if we were breathing, but there were two factors in force, not just size, but direction.
Unlike force, a physical quantity that has no direction and only size is called scalar in jargon.
Scalar's addition is simple. We can use numbers.
1+1=2, 2+2=4 It's simple, right?
But how do I add the direction?
There are east and south here.
Now let's add these two directions.
It's a very absurd addition.
But there are a few possibilities to think about.
The first is to add east and south angles to the north.
So it's going to be west?
I don't think it's such a good idea.
So most people probably think of the following methods.
Take the middle east and south.
First of all, it's exactly like Newton thought it would be vector addition of vectors.
Ah! vectors are physical quantities that have dimensions and direction, like force. There's acceleration, speed, and so on.
But vectors have not only orientation, but also size.
Then how do I add two to the east and four to the south?
To think and prove how to add vectors
Newton did this again.
Newton said that force is to change the speed of an object in the direction of force.
If the force is applied when the object is stationary, the object moves faster and faster in the direction of the force.
If the object is moving, the speed of the object will increase if the force is applied in the same direction as the movement.
If the force is applied in a direction opposite to the direction of motion, the object will gradually slow down.
This is the famous Newton second law.
It's a law of acceleration called F=ma.
Let's take a look at Newton's book, "Principia," to find out how Newton proved the addition of vectors.
Assume that two forces, A and B, worked simultaneously on an object.
If only the force of A applied to an object, the object has 1 direction and 1 travel distance for some time t. (Let's just say one second here.)
If only B force applied to an object, it would have 2 directions and 2 distances in a second.
Because force changes speed in the direction of force.
The force of B did not affect the speed change in the direction of A force.
So even if two forces work,
The object must have a travel distance of direction 1 caused by force A.
However, the speed generated by the force of B continuously changes the position of the object as it moves in direction 1.
If you draw a line parallel to route 2 at the end of route 1,
The object somehow meets at a point on this line after a second.
Let's think the other way around this time.
An object must have a travel distance of direction 2 created by force B.
However, the velocity generated by force A continuously changes the position of the object as it moves in direction 2.
If you draw a parallel line to Route 1, at the end of Route 2, the object somehow meets somewhere on this line in a second.
In two cases, because the meeting points must be the same, it should be considered that objects move along the diagonal path of the parallelogram when they are drawn using two paths.
So, for a second, the force that causes an object to travel along this path,
It's the sum of the A and B forces.
Then define the direction of path 1 and the length of path 1 by size.
Then B force is the direction and size of Route 2.
The force of the two forces can then be obtained by parallelogram.
The diagonal direction is the direction of the force and the length is the size of the force.
It might be a little difficult, so shall we explain it from a modern point of view?
First of all, we're going to talk about speed, except for the power Newton talked about.
Speed is also a vector of direction and size, so knowing the addition of speed is the same as knowing the addition of force.
The current era displays vectors as arrows.
The direction of the vector, the length of the arrow, is the size of the vector.
Some objects have speeds of A and B.
Imagine a RC car lying on a large treadmill.
You're outside controlling that RC car.
The treadmill moves at a speed of 1 m/s in the direction of A.
Above this, the RC car moves at a speed of 2m/s in the direction of B.
So you can tell that RC cars have A and B speeds.
If the RC car moves 2m for 1 second in the B direction,
the treadmill always moves the RC car 1m in the A direction.
So RC cars eventually move like this for a second.
In two seconds, the RC car will move 4 meters in the B direction, 2 meters in the A direction.
The length of the sides of the triangle is doubled.
The ratio for the length of each side is always constant regardless of time.
So you can define the addition of two vectors like this.
There is a vector called A.
There is also a vector called B.
The ratio of the length of the two vectors is the same as the ratio of the size of the two vectors.
So the sum of the two vectors is to connect the beginning and the end points to create a new vector.
It's the same shape as the diagonal of the parallelogram.
The direction indicated by the arrow is the direction of the vector,
and the length of the arrow can be determined by the size of the vector. By using proportionality.
If you reverse the vector synthesis, you can divide one vector into two vectors.
We can divide the power of C into the power of A and B.
This is a very powerful weapon when we solve problems or interpret natural phenomena.
You may resent Newton for making such a complicated thing difficult for himself.
But if you know what Hamilton did in the future,
you'll know Newton was an angel.
Let's cheer up until then.
What if you want to see this blog on video?
Comments
Post a Comment