Parachute comprehensive simulation training base.

Qian Youzhi saw that Tuoyong had just fallen into a daze, so he set his eyes on Wu Zhe.

"39, if it were you, would you be worried about skydiving training with a sudden increase in altitude?"

Listening to Director Qian's question, Wu Zhe nodded slightly.

"Although I know that in theoretical mechanics, there is a theory about the speed of falling high-altitude objects, and there is a limit speed, but I have not been deeply involved in the specific content, so I dare not try it easily."

Qian Youzhi sighed and looked at Su Qiyue again.

"Number 43, what about your choice?"

Among this group of trainees, Su Qiyue is also one of the objects of Qian Youzhi's attention.

Not only because of his academic qualifications, but also because of his stable psychological quality.

In fact, for the training subject of skydiving, after systematic training, the technical gap is very small.

The main thing is to see who can be more calm and have a better psychological quality.

Hearing the instructor's question, Su Qiyue said calmly: "I will accept it." ”

"Oh? The reason? ”

Qian Youzhi asked with squinted eyes.

"The closing speed of the human body falling from a high altitude is about 70 m/s. After reaching a certain altitude, there is no difference in speed when you skydive down from a certain height. ”

"In the case of good protection, the only difference in skydiving altitude above 3,000 meters and below 5,000 meters is only the difference in the time of parachuting."

Listening to Su Qiyue's eloquent talk, Yuan Lang, who was standing next to Qian Youzhi, came to his senses.

"Finishing speed? Can you explain it in more detail, 43? ”

Yuan Lang tilted his head and said.

Qian Youzhi was obviously also interested in the answer given by Su Qiyue, so he smiled and said, "Yes, 43!" ”

"You turn your head and see, everyone is in a fog about your answer, you might as well give everyone a science popularization, so as to reduce everyone's psychological pressure......"

Su Qiyue glanced at Tuo Yonggang and Wu Zhe beside him, and found that these two comrades-in-arms were looking directly at him.

Xu Sanduo, who was a little farther away, blinked his eyes and looked curious.

He muttered for a moment before he began to organize his words.

"In fact, it is not difficult to understand that there will be a closing speed for falling objects from high altitudes."

Su Qiyue raised his head and said: "It's like raindrops falling from such a high place, they won't kill people, the reason is the same." ”

"Let's take raindrops falling from the sky as an example."

"Once the raindrops fall from the sky, they don't keep accelerating. It will be subject to the resistance of the airf. This f is proportional to the square of its velocity. The higher the speed, the greater the air resistance. ”

"During a high-altitude fall, there will always be a point in time when the air resistance will be equal to the gravity of the raindrops. At this time, the raindrops enter the finishing speed and do not change. ”

Hearing this, Wu Zhe's face showed a look of relief.

Su Qiyue paused for a moment, and then said: "According to a formula given by physicist Rayleigh, air resistance f=1/2· V?? ρ· Cd·A。 ”

"where V is the velocity, ρ is the density of the air, Cd is the coefficient, which is related to the shape of the object, and A is the opposite area of the object when it falls."

"Because when the air resistance and gravity are the same, the falling velocity does not increase. Therefore, if you want to know the closing speed of the raindrops when they fall, you only need to substitute the gravity value into the air resistance f. ”

"After conversion, V?? =2mg/ρ· Cd·A……”

Listening to Su Qiyue's explanation, the comrades-in-arms around him all had shocked expressions.

"On the premise that the shape of the falling object is approximately spherical and the density is about equal to the density of water, this formula can be simply summarized as V=90√d. where d is the diameter of the object. ”

"We substituted the average diameter of the raindrop by 2 mm, and the result was that the closing speed of the raindrop was only 4 m/s."

"That's why raindrops don't kill people......"

Listening to Su Qiyue's answer, Qian Youzhi's face was very exciting.

Originally, he just wanted to wake up Tuo Yonggang and make him a little in awe of tomorrow's skydiving training.

Unexpectedly, it led to such a large number of theories as Su Qiyue.

Barely calming down, Qian Youzhi said gently: "So according to your theory, the closing speed of a person is about 70m/s?" ”

Su Qiyue bowed slightly: "Under normal circumstances, it is true. Of course, everyone's body type, and posture when jumping, is different. In the end, reflected in the finishing speed, there must be a slight difference. ”

"However, the magnitude of 70m/s must be right."

Su Qiyue finally concluded: "According to this theory, the daily altitude of our army's parachute training is around 3,000 meters, which is still very reasonable!" ”

After listening to Su Qiyue's story, Qian Youzhi shook his head with a wry smile, and couldn't help but give him a thumbs up.

"I've been teaching skydiving for so many years, and this is the first time I've figured out the theory. Go back and sort out what you just said, it's enough to write a paper......"

When Qian Youzhi spoke, Yuan Lang and Qi Huan next to him also woke up in astonishment.

After taking a deep look at Su Qiyue, Yuan Lang coughed and said, "Okay, today's training is here." Qi Huan, take them to run a 10-kilometer cross-country, and it's better to eat early when it's over! ”

"Yes!"

Qi Huan answered, and led the special training personnel out.

After the people at the training base dispersed, Qian Youzhi sighed to Yuan Lang and said, "Deputy Chief of Staff, there is really a hidden dragon and a crouching tiger in this batch of soldiers." ”

"That 27 is in no way inferior to me in terms of skydiving; No. 39, the key training object of the Master of Optoelectronics and the Marine Corps; As for the number 43, it's even more remarkable......"

Listening to Qian Youzhi's emotion, Yuan Lang showed a mysterious smile.

……

On the playground, Tuo Yonggang, who had just started running, came to Su Qiyue's side as soon as possible.

"July, I said you're a little more knowledgeable, aren't you? Did you notice just now, your words directly scared Director Qian stupid! ”

Listening to Tuoyonggang's exaggerated words, Su Qiyue shook his head amusedly.

On the other side, Wu Zhe also said: "Yes, July, your foundation in theoretical mechanics is too solid, right?" I'm really convinced! ”

Seeing that Su Qiyue did not respond to him, Tuo Yonggang turned his target to Wu Zhe.

"I said normal heart, don't you also have a master's degree? Why can't you answer the theory that July said? ”

"Damn, I'm a master's degree in optoelectronics, not a master's degree in theoretical mechanics!"

Wu Zhe took a sip and said dissatisfiedly.

Takunaga just smiled and teased: "Look at what you said, it seems that we are a master's degree in theoretical mechanics in July......

Thinking of Su Qiyue's research direction during his graduate studies, Wu Zhe was suddenly speechless.

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