Football is definitely not round, why is football round?

The 2010 South Africa World Cup special ball, when it was designed, was called the "closest" round football, the problem is very clear, the closest is not equal, but only approximately equal, then the football pushed forward is naturally not a complete circle.

There is no absolute thing in the world, such as no absolute circle, of course, there is no absolute circle of football, but what the landlord said is so absolute, hehe.

Putian O Tongqing" specification parameters with 7 x is "Putian I Tongqing" specification parameters and UFIFA standard comparison 5: Circumference 6: "Putian J Tongqing":

。Centimeters FIFA Standard: Centimeters Roundness:

To measure the diameter of the soccer ball in 62 Q different places 5. "Putian Z Tongqing": Maximum R Error FIFA Standard:

Maximum S Error Water Absorption 4 Sex: Football to 230 times in 8 in water "Putian A Tongqing": Zero weight gain FIFA standard:

Maximum Q weight gain 20% Weight "Putian x Tongqing": 210+. g FIFA Standard:

720-470 g Anti-8 elastic performance: In the test, 7, the football should fall from a height of 7 two meters to the steel plate, and repeat it 10 times in one d. "Putian d celebrates":

The height of the anti-7 bomb is between 782 and 714 cm FIFA standard: The difference between the height of the highest and lowest anti-2 bombs in 30 times is not higher than 10 cm of A10 cm Pressure Z loss: The pressure of air 1 is measured after 77 days of inflation.

Putian P Tongqing": Maximum T pressure loss 70% FIFA standard: Maximum W pressure loss 20% "Putian C Tongqing" is not made of 12 balls sewn by hand 5 workers, but is made of 7 balls thermally bonded, which has higher roundness and stronger water resistance.

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"Universally celebrated" specifications.

The following is a comparison of the specifications and FIFA standards of "Celebration of the Whole World".

Circumference: "Universal": - centimeters FIFA standard: centimeters.

Roundness: The diameter of the ball is measured in 16 different places.

"Celebration of the whole world": maximum error FIFA standard: maximum error water absorption: the football needs to be pressed 250 times in water.

"Celebration of the whole world": zero weight gain FIFA standard: maximum weight gain of 10% weight. "Celebration of the whole world": 440 - g FIFA standard: 420-445 grams.

**Performance: In the test, the ball was dropped from a height of two meters to the steel plate, which was repeated 10 times.

The height of the :* is between 143 and 149 cm according to FIFA standards: the difference between the highest and lowest** heights in 10 times is not more than 10 cm.

Pressure loss: Air pressure is measured after 3 days of inflation.

"Putian Tongqing": maximum pressure loss 10% FIFA standard: maximum pressure loss of 20% "Putian Tongqing" is not made of 32 balls sewn by hand, but is made of 8 balls thermally bonded, which has higher roundness and stronger water resistance.

There are no absolutes, everything is relative.

In a strictly mathematical sense, it certainly wouldn't be an absolute circle.

Symbolically, football is even less round.

01 The first is that the ball with filial piety can reduce the pain, the second is that the round football rolls faster, and the third is that the flight trajectory of the round football is controllable.

In fact, strictly speaking, football is a sphere, and because of the colloquial expression, we generally say that football is round.

Football is round mainly because:

1. A round soccer ball can reduce pain. When an athlete kicks a ball, his feet come into contact with the ball. The athlete uses his foot to exert a force on the soccer ball to make it move in the direction he wants.

If the soccer ball is angular, the area of contact with the foot is smaller when the player kicks the ball, and the pressure will be greater, and such a force will be painful to the foot. However, if the soccer ball is round, the contact area of the foot will be relatively large, and the pressure on the foot will be smaller, so the pain will be greatly reduced.

2. The round football rolls faster. We know that motion creates friction, such as when a clump applies a force to an object to move on the surface of another object, and the friction that occurs hinders its motion. The soccer ball is a sphere, and the motion of the sphere produces rolling friction; For other shapes, sliding friction is often generated.

From life experience, we know that scrolling is always less effort than sliding. Therefore, the spherical object will maintain a fast speed and maintain a long time of motion during the forced rolling process.

3. The flight trajectory of the round football can be amused. We all know parabolas and arcs, on the football field, if you want to control the trajectory of the football, kick a beautiful arc, and score a perfect goal, only a round football can do it well.