The quadrennial Olympic Games has just come to an end. Looking back on this Olympic Games, before the opening, the preparation and promotion of the Olympic Games have attracted the attention of all parties. As the curtain of the Olympic Games officially opens, athletes from all over the world are also presenting us with a unique sports event in the stadium.
However, every Olympic Games may be different, but the basic rule that governs all sports remains the same, and that is physics. In fact, many physicists are also sports fanatics. Let’s take a look at their favorite sports and the physical principles involved.
When the physicist won the Nobel Prize, the title of a media press release was this: Football player Niels Bohr is awarded the Nobel Prize in Physics.
When Bohr was born, modern football was still a new thing in Denmark, but his father introduced the sport to the local area and built a football stadium. Every time he went When traveling, he would take his two sons with him: Bohr and Harnard. This led Bohr to love football since childhood and to participate in professional football matches at a young age. He served as goalkeeper for AB Copenhagen, one of Denmark's most famous teams in the early 20th century. His younger brother Harnard, who later became a mathematician, even competed in the 1908 Olympics as a member of the Danish national football team, eventually winning a silver medal.
In the end, Bohr felt that solving problems was more interesting than goalkeeping. Bohr gave up football and chose to enter the University of Copenhagen to major in physics. However, he also served as the goalkeeper of the university football team during school. When he focused on professional research, he discovered that footballs and electrons follow completely different laws of motion, so size must have had an impact. Quantum mechanics pioneered by Bohr helps us understand the wonderful phenomena of the microscopic world, while classical physics can explain the movement of the macroscopic object Bohr loved, football. However, the macro-level football movement does not seem to be so easy to predict. In 1997, Brazilian football great Roberto Carlos shocked the world when his free kick flew into the goal through an incredible route.
According to Newton's first law of motion, any object must maintain uniform linear motion or rest until an external force forces it to change to the motion state. When a player kicks the ball, it gives the ball direction and speed, but what force makes the ball turn? The key to the banana ball is "spin". The difference in air flow speed on both sides of the ball changes its path of movement. The ball travels through the air, and the oncoming airflow flows around the ball. The airflow generated by the counterclockwise rotation on the left side is superimposed on the oncoming airflow, so the airflow speed becomes faster. The airflow generated by the clockwise rotation on the right side offsets part of the oncoming airflow, so the airflow slows down.
According to Bernoulli’s theorem , the pressure on the left side is small and the pressure on the right side is strong. The airflow has a tendency to flow from right to left. According to the Magnus effect, the pressure difference between the left and right sides causes the ball to generate a lateral force. This force causes the ball to eventually move to the left and fly into the goal.
This is the student of the football enthusiast in front - Werner Heisenberg.
Heisenberg is an extrovert. He is not only academically accomplished, but also good at music, languages, mountaineering, and table tennis. It is said that he was unmatched in all the games at the University of Leipzig and was very competitive. It was not until 1928 that a Chinese student came to Germany to study quantum theory with Heidelberg. From then on, Heisenberg's table tennis level changed from the first in the school to the third. two. And this student is Zhou Peiyuan, Yang Zhenning’s teacher. Zhou Peiyuan admired the young professor's talent in physics, and Heisenberg also recognized Zhou Peiyuan's knowledge. The two were similar in age and also liked playing table tennis very much, and they got along very well. Before Zhou Peiyuan went to the United States to give lectures, he even held a table tennis tea party. Later, Heisenberg repeatedly praised Zhou Peiyuan's character, work attitude, academic quality, and table tennis skills that he would never forget in public.
Speaking of table tennis, we have to talk about its unique spin. A table tennis ball can have considerable spin in any given direction, and players use spin for two reasons: First, a spinning ball has a completely different trajectory than a non-spinning ball, which allows the ball to Reach angles and positions that are impossible to reach without rotating. Secondly, it is more difficult for opponents to react to a spinning ball.
If you are facing the top When you catch a ball with spin, the ball will give a downward friction force to the racket surface, and the racket surface will give an upward reaction force to the ball, so the topspin ball you catch will easily fly into the sky.
If you are facing a backspin ball, when you catch the ball, the ball will give the racket an upward angle Due to friction, the racket surface will give the ball a downward reaction force, so the ball can easily penetrate the bottom of the net.
There is also a strange phenomenon. If the backspin ball bounces onto the table, it will move the table forward. The friction force of the table gives the ball a backward reaction force. If the ball is traveling fast enough, it may move backward toward the net.
The rotation of the ball is mainly caused by the friction between the ball and the rubber. If the particles on the positive side of the rubber face outward, the ball will be hit at a slower speed but with a faster ball speed; if the particles on the reverse rubber side are facing inward, the ball will be hit at a faster speed and with a faster speed.
Oxford University’s rowing team has a history of nearly 200 years. An unexpected physicist was a member of the rowing team at Oxford University (pictured below, right). He serves as the helmsman. From the picture, it seems that he is indeed not a strong man.
But you must never have imagined that he is the most popular contemporary person. The great physicist——Stephen Hawking! Although we remember Hawking as being confined to a wheelchair for most of his life, he was actually a member of the Oxford University rowing team before developing amyotrophic lateral sclerosis. Since the helmsman does not participate in rowing, Hawking, who is thin and loud, became the ideal candidate for the helmsman.
To be selected as the helmsman, Hawking really has a physical advantage. Rowing can be said to be the fastest water sport. The weight of people and equipment is one of the key factors that affect the speed of rowing. The greater the weight, the greater the resistance that needs to be overcome when rowing forward. There are strict regulations on the weight of equipment. Each team will weigh its own rowing boat before the competition. If the weight is lower than the standard, lead weights must be added to increase the weight. If we want to effectively reduce weight, we can only start with human weight, so we came up with the idea of a helmsman who does not participate in rowing. In the 1900 Olympic Games, in order to win the championship, the Dutch team even replaced the adult coxswain with a 7-year-old French boy in order to reduce weight and thereby reduce the resistance of the rowing boat! However, in order to prevent this phenomenon, the rules of rowing competition have been changed. Racing boats were not as "slim" as they are now. The shape gradually became narrower during the evolution. The width of modern rowing boats is 57 cm for eight-person boats and only 30 cm for single-person boats. This is also to reduce water resistance. In addition, the rowing oar was originally a laborious lever. In 1846, the British installed oar racks extending out of the boat on both sides of the racing boat, increasing the length of the oars and greatly extending the power arm. In this way, the athlete can use less force and the boat can gain greater power. These measures have helped rowing become the king of speed in water sports.
They are not the only sports fanatics in the physics world - Carl Sagan was the captain of the school basketball team in middle school. Einstein was an avid walker and walked 5 kilometers to work every day. However, he is far behind Tesla. Tesla was extremely self-disciplined and walked 12 to 16 kilometers every day. Qian Weichang, an internationally renowned nuclear energy scientist, is good at track and field. Participated in the National University Games and won the top three in the 100-meter hurdles. ... The physicist Newton, who is famous for studying the laws of motion, is not on the list this time. It is true that the editor has not found a sport that he likes, but it does not prevent his theory from directing various sports.
References
[1]https://davidson.weizmann.ac.il/en/online/sciencehistory/scientist-who-found-difference-between-quantum-particle-and-soccer-ball [2]https://gregsttpages.com/archives/general-articles/the-basic-physics-and-mathematics-of-table-tennis/[3]https://davidson.weizmann. ac.il/en/online/askexpert/physics-table-tennis-aka-ping-pong
[4] CCTV documentary "My Coach Newton"
[5] Book "My Coach Newton" 》
[6] "I, Heisenberg"
[7] "Physics" Issue 2, 2010, "Heisenberg and the Chinese Physics Community" Jin Zhongyu, Wang Shiping Spanish "Interest" monthly magazine January No.
This article comes from the WeChat public account: WeChat public account (ID: null), author: Translation Column
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