The rune Institute, Odin island.

In a large conference room, Renault, with both hands on his back, stood in front of a large blackboard and talked endlessly.

Under the stage, a black head was listening to the Lord''s story, while writing on the notebook on the wooden table.

"In these two days, we have talked about the three laws of motion of Reynolds, namely, the law of inertia, the law of acceleration and the law of reaction force."

With Renault''s words, three pieces of chalk automatically fly up from the table, while writing three laws and corresponding formulas on the blackboard.

"There is a very interesting example of their specific application. Why do the shoelaces loosen?"

"Does anyone know the answer?"

At this point, he deliberately stopped and scanned a circle of more than a dozen magic mechanics and more than 50 apprentices.

This is the little skill Renault learned on earth, a very "cheap" skill - asking questions.

When doing training, if you ask questions from time to time, you can effectively let everyone focus and greatly improve the training effect.

The reason is very simple. People who participate in the training will subconsciously worry: what if the goods suddenly ask me questions?

It''s humiliating not to answer. What should I do?

Out of this subtle psychology, they will listen carefully. Few people dare to wander.

Although as Lord, there is absolutely no one who dares to be absent-minded in Renault''s lectures, this guy loves to play this trick.

The more frightening it is, the more profound the memory is.

In the face of the Lord''s bright eyes, everyone unconsciously avoided and did not dare to look at him.

On the one hand, because no one knows the answer, on the other hand, because of awe.

But Renault didn''t expect them to answer that either.

several boring scientists on the earth used high-speed cameras, and installed accelerometer sensors on shoes to understand the real reason for shoelace''s dispersal. The group of woodlouse didn''t learn physics very long before they could answer it.

He waved his right hand lightly, and a piece of chalk quickly outlined the appearance of a boot on the blackboard. The laces on the boot were especially large, which was to highlight the laces.

"According to Renault''s third law of motion, the action of forces is mutual, that is to say, the acting force and the reaction force must appear at the same time."

"Every time a boot lands, it will produce a pressure on the ground. At this time, the boot will also be subject to the reaction force of the ground. This force will be transferred from the boot to the laces, causing an impact on the laces."

"When the boot repeatedly raises and falls to the ground, the shoelace will be repeatedly impacted, and finally the knot of the shoelace will slowly loosen."

"No matter how tight the tie is, it will loosen, but the tighter the tie is, the longer it takes for the tie to loosen..."

At this point, the chalk automatically approached the blackboard, drew an arrow above and below the boot to indicate "force and reaction", and wrote "Reynolds'' third law of motion" next to it.

The audience quickly followed suit and drew boots and arrows on their notebooks.

"But this is only one part of the reason for the laces to spread, and the other part is related to Reynolds'' first law of motion, that is, the law of inertia."

"When you walk in boots, the movement state of the boots will change back and forth between" stationary "and" moving ". Due to the inertia effect, the ends of the laces will swing back and forth."

"When you step forward, the end of the shoelace will swing back. When the boot falls to the ground, the end of the shoelace will swing forward. In the continuous swing, the loose shoelaces will slowly spread out."

In Renault''s description, the chalk drew an arrow on the left and right of the boot, and wrote the line "Renault''s first law of motion".

Then he began to summarize.

"Therefore, the real reason for the laces to spread is due to the cross action of two forces: the reaction force of the ground makes the knot loose; the inertia force of walking makes the laces open."

"Simple stomping up and down, or swinging back and forth, are not enough to let the shoelaces spread, it must be the combination of these two forces..."

Hearing this, all the faces were suddenly enlightened and looked at the LORD with admiration.

The original principle of Raynaud''s "three rules of sandal movement" was so clear that they could say it for the first time.

This is the course that Renault recently taught himself at the institute physics.

This shameless guy, when popularizing physics knowledge to his Rune magicians, shamelessly changed the names of many laws and theorems into his own.

The "Newton''s three laws of motion" on the earth has become the "Reynolds''s three laws of motion" in a different world.

In addition, light reflection and refraction, as well as pressure, pressure, buoyancy, conservation of energy, gravity and so on, all leave a deep mark on someone.If it wasn''t for the absence of "electricity" and "magnetism" in the alien world, I''m afraid his knowledge in this field would not have escaped his vicious hand.

But Renault is very proud of this: in this world, the master is the first to speak out this knowledge and spread the seeds of civilization. I have no credit. Why not leave a name for him?

This kind of crazy "plagiarism" has a remarkable effect. In the eyes of many magicians, their Lord is the first wise man of the human race in history.

* * *

"bang!"

Renault was about to explain "acceleration" in depth when there was a heavy dull noise outside the door. He rushed to the door and looked up.

A gray figure from the air quickly skimmed, quickly flew to the distance, soon became a small black spot.

Adanis!

Renault sighed with some headache and turned to look into the yard.

As expected, a small animal was lying on the snow motionless, with a large amount of blood on the spotless ice and snow.

The animal is less than half a meter long, with snow-white fur and light gray spots on its surface.

This is the chipmunk.

Obviously, this is the prey that adanis captured again. The little female cat knew that Renault was in the Research Institute and even sent the prey here.

Since the last time he jumped over the cliff, the little thing has completely activated his nature. Without Renault''s instruction or supervision, he began to actively practice gliding.

At the beginning, it also needs the help of terrain, such as cliffs, gliding time is not long, but with the improvement of proficiency, its gliding skills become stronger and stronger.

Just a month later, it can start on the roof. Now, as long as the wind is a little strong, it can fly to the sky on the flat ground.

In addition, Renault often gives adanis magic energy crystal. The magic energy level of the little guy increases very fast. The wind element gathered in its film wing increases several times. Correspondingly, its flight time also increases several times.

Renault deliberately tested it a few days ago. The little thing followed him for nearly two hours in the wind before landing on the ground, and this is not the limit of it.

The reason why the little guy stopped was that it was so cold in the cold winter month that he didn''t want to fly any more. Renault touched its film and found that there was still a lot of wind elements in it. It would be more than enough to fly for another two hours.

Obviously, adanis has grown into a real "flying cat".

As for the chipmunk that came down from the sky, there was another thing involved.

It was something Renault regretted.

He glanced at the bloodstain in the distance and scolded bitterly: "dog day''s'' ground mouse ''..."