white tour

The turmoil outside the court continued. Facing those who kept criticizing him, Ronaldo finally launched a counterattack.In the just-concluded two world preliminaries, he helped Portugal easily win 6 consecutive victories with a score of 0-2 with a big four and a world wave. Leading the way, the state is still the top in Europe.

While people are sending praises to Ronaldo, there are also good people trying @Antonio to let him see the gap between the two.Although it ended because Antonio's social account could not be found, it still aroused fierce scolding from fans on both sides.

At this time, Antonio realized that he had so many fans, or is it more appropriate to call him "Rohei"?

Antonio no longer pays attention to these. He is very tired every day, and it takes a lot of time and energy to make up for the missing training.

At night, all the lights in the backyard were turned on, the green turf was a little whitish, and the entire small stadium was brightly lit. A little to the right of the center line—a pile of footballs were scattered about 30 meters away from the goal.

Antonio pulled a football over with his feet, and after placing it, he got up and backed away. He looked at the goal, fixed his position and looked back at the football six steps away in front of him, and then it was a run-up!Swipe your right foot!shoot!The football was kicked out by him, drew an arc in the air, and went straight to the upper right corner of the goal.

"Swipe!" - This is the sound of football hitting the net, but Antonio still shook his head, he failed.

What went wrong?Is it lack of strength or the wrong position to touch the ball?Antonio frowned and pulled a football over again.

In the living room, Mini Luo was sitting at the desk doing homework.After finishing the stretching exercise, Ronaldo quickly took the massage cream and massaged himself. The reason for this was because he wanted to reduce his muscles.

Although he has made a lot of efforts to gain muscle before, Ronaldo clearly knows that he is no longer young when he is over the age. The change of style of play and position on the court has turned too many muscles into a burden.So if he wants to continue to maintain his scoring efficiency, if he doesn't want to fall behind his old rival Messi, if he still wants to realize his dream of dying in the Bernabeu, muscle reduction is imperative.

What he had obtained with all his efforts and efforts had to be given up in an instant. This pain was felt by Ronaldo, but he will not be sad, and he has no time to be sad, because he is still trying to find his own. state.

After taking a shower, C Luo went to see Mini Luo first, and then he went to the kitchen and poured himself a glass of orange juice. When he inadvertently looked through the window and saw the sweaty figure in the night, he couldn't move his eyes away.

That bastard next door, is he practicing the elevator ball?Frowning, Ronaldo drank the orange juice at the bottom of the glass.

fail!fail!Still fail!After another miss, Antonio stopped.

"Annie, take a break!" Jesús caught the ball that hit the wall and bounced back, "You've been practicing for over an hour, don't your feet hurt?"

Antonio beckoned to Jesús to throw the ball over, but the agent threw the football behind him.

"I want to train you alone! I don't want to be your caddy anymore, and you can pick up the balls that fly outside!" Jesús, who was rejected again, got angry and went back with his hands behind his back. in the room.

Antonio froze for a moment, then silently pushed the basket and walked forward to pick up the footballs scattered near the goal.After that, he returned to the spot with a basket of footballs and continued to practice again.

Jesus, who was peeking behind the door, kicked the wall angrily. He knew that his apple tree was under a lot of pressure because people have been comparing it to Ronaldo recently, but he could abuse himself in this way. ?

"I really don't care about him this time!" Jesus clenched his fist and kicked the wall angrily.

"Hey! Are you practicing elevator ball?"

Antonio turned around and found that it was Mr. Ronaldo, his neighbor. He stood there with his arms folded and his face arrogant, and he abruptly put on his bathrobe like a dragon robe.

How did he get in?Oh, our house has no gate!Wearing a white bathrobe made Mr. Ronaldo look even darker, but why did he come here... For a moment, Antonio thought a lot.

"Hello, Mr. Ronaldo, what's the matter?" Although puzzled, Antonio nodded politely.

"It's because you have something to do!" Ronaldo's eyes were full of coldness, "After practicing for so long, no one has succeeded. Do you know how the elevator ball is kicked out?"

"Yes," Antonio nodded, "Different from the 'Magnus effect' of the curve ball, the elevator ball follows the 'vortex effect'. The basic formula of the vortex theory is very simple, that is, F is equal to V being B is divided and multiplied by K. V is the running speed of the sphere, B is the diameter of the sphere, and K is the Strouhal number, which is the frequency of shaking. From this formula, it can be seen that the faster the ball speed, the greater the diameter of the sphere The smaller the size, the higher the frequency of the football shaking. The diameter of the football is fixed, and the Strouhal number is relatively fixed, so the only thing that can play a role is the speed of the ball, which depends on the speed you apply to the football. Power, that is, the power of your shot. So the greater the power of the shot, the higher the frequency of the football shaking in the air after being affected by the vortex theory. This is why the elevator ball will go up and down, left and right in the air For reasons like Juninho's 'B' free-kick which was considered to violate the laws of physics."

"The strength required to kick a ball can be calculated in theory, which is related to a ratio called the Reynolds number. The Reynolds number refers to the ratio of the force you kick a ball to give it and the sticking force of the air to the football. Through I found that for a non-rotating ball, when the initial speed is less than the end speed, the ball will move in a parabola, which is the arc ball. And when the initial speed is much greater than the end speed, the ball will appear sharp when it falls. Falling phenomenon, which forms the elevator ball. The basic formula for calculating force is Newton's second law!"

"According to Newton's second law... the elevator ball does not rotate, so the value of the lateral force can be ignored, so when only air resistance is considered, this formula can be simplified to..."

"...According to this formula, a final speed can be finally obtained, which is a square root form, related to the radius of the ball, related to the drag coefficient, and also related to the air density. The difference between the final speed and the initial starting speed The relationship determines the trajectory of the ball."

Antonio squatted down and drew an unclear xy axis on the grass with his fingers.

"Look at this arc! The initial speed is about 17 meters per second, and the angle is eighteen degrees. The calculated arc is a typical elevator ball running line..."

stunned! C Luo felt that he had suffered a critical blow from a school bully!He unconsciously withdrew his arrogant posture, and squatted on the ground with Antonio, his mind was full of "Who am I? Where am I? What am I doing?" The screen was swiped in a loop.

"So, if you want to kick the elevator ball, the strength of your calf is the most important thing!" Antonio just wanted to habitually ask "Do you understand?" when he remembered that the elevator ball was the person in front of him He is good at it, so he abruptly turned the syllable, "Do you... think so?"

I never knew that I had to do math problems to play football!Or is it mixed with physics? Ronaldo was silent, looking at the brown-haired youth like looking at an alien.

Being stared at by this kind of eyes, Antonio felt a little flustered. He put in the formula and calculated it in his heart again, but he couldn't find any mistakes in it.

"Is there a mistake in my calculation, or is the formula itself wrong?" Antonio tapped the grass under his palm, "Even if the deviation value is added, it's not right! The elevator ball hardly rotated during the flight, and the football went straight. Going up makes people mistakenly think that it will go directly above the crossbar, but then it suddenly falls and rubs against the goal post and flies into the goal. But all I kick are with spin, this is a curved ball, both fall and spin It's the fallen leaf ball!"

"You kick one and let me see!" Hearing this, Ronaldo stood up and nodded towards the goal with his chin.

Antonio put the football down obediently, and then kicked the ball out with a few steps of running up and swinging his calf.

The position of the valve core is just in the middle of the football get√ run-up distance... Well, there is a problem with this!Basically, the stance is in a straight line with the football and the goal. Get√Run on the soles of your feet when approaching get√The part that touches the football...is the arch of the foot?This is a big mistake!The middle and lower part of playing football get√ Use the knee to drive the calf to exert force get√...

"Don't use the arch of the foot, kick with the toe, or straighten the instep! Also, your run-up distance is too far. Beginners should be closer to the football." Ronaldo saw the problem at a glance, and he stood aside , commanding Antonio to make adjustments in a cold tone.

"No arch..." Antonio tried again, his eyes became brighter as he watched the flying football, "Yes! The smaller the contact surface between the foot and the football, the better. There will be no rotation. So, how did you calculate this force, Mr. Ronaldo?"

How do I know, isn't it based on feeling? C Luo folded his arms, remembering just now, he felt annoyed that he was slapped in the face instead of pretending to be coercive.He coughed and said vaguely: "Practice more, you will know it naturally!"

No one spoke anymore, and the atmosphere was a little awkward.

The two looked at each other, Ronaldo's eyes widened and he was unwilling to look away first, Antonio blinked and backed down.

Ronaldo was very proud, because he won another victory, although he soon shuddered because of the night wind.

Antonio laughed, "Cristiano... can I still call you that?"

"Isn't the name just for calling?" Ronaldo stepped on the turf under his feet awkwardly, then lowered his head and whispered back.

The author has something to say: So whoever wants the schoolmaster Annie! ∏_∏