Why is the 2010 World Cup ball difficult to kick?

The players who are attending the World Cup in South Africa find many unusual phenomena in the shots because they are playing football in a place as high as 1,680 m.

Livescience said, the higher the height, the lower the air pressure, the lower the air pressure, the faster and faster the ball moves.

'When players play in Johannesburg, the ball will move in a completely different way than when they are in low places due to differences in air density. If you watch recent matches, you often witness the ball flying too far from the player's position in long passes. I think low air pressure causes that phenomenon, ' commented Rabi Mehta, an aeronautical engineer at the US Aerospace Agency (NASA).

When the ball rolls on the field or flies in the air, the resistance of the air will cause its speed to decrease, and the lift force of the air will make it fly up in a curved orbit. As the density of air decreases, both resistance and lift are weaker. So if the player kicks in midair in Johannesburg, the ball will move faster and more straight than the same shot in low places.

Many goalkeepers make unjust mistakes.Photo: sportpost.com

Mehta said that players who are aware of the impact of altitude on aerodynamic principles will have an advantage over other players.

'When a player wants to make a long pass for a teammate, he has to kick the ball with a lighter force than usual, because otherwise the ball will fly over the required position , ' Mehta explained.

On the other hand, when the player kicks the ball into the opponent's goal, the keeper easily catches the ball and lets it slip into the net. In the match between England and the US team on June 12, England goalkeeper Robert Green let the ball slip out of his hand and into the net after a shot from the American player. Many people believe that the big bounce of the ball and its unpredictable movement make Green goalkeeper mistake.

Mehta also studied the factors related to the aerodynamics of Jabulani - the ball is being used at World Cup 2010. Many players complain that the ball moves faster and has greater bounce. So players and goalkeepers easily lose the ball when it is kicked. The biggest problem with this ball is that it often redirects very unexpectedly. The reason was that the Jabulani ball did not rotate as it flew in the air.

The Jabulani ball has no perfect smoothness because it has many grooves between 8 pieces. Besides, it also has floating edges. The presence of burrs and grooves creates an asymmetric air around the ball. The asymmetric forces of the air make the ball easy to change direction.

In addition, Mehta said that players may face many physical problems when playing in places that are too high compared to sea level. More dilute air means they take in less oxygen. So players will have to breathe harder and more to get enough oxygen into the muscles. In fact, people have a mechanism to adapt when altitude changes. For example, when the height is greater, our body will produce more red blood cells to increase the amount of oxygen in the blood. But the production of extra red blood cells takes a lot of time. So players who live in countries with a height above sea level or coming to South Africa soon enough will adapt to the thin atmosphere here.