During the EURO2020 matches, Lorenzo Insigne showed off his famous “tiraggir” on several occasions: let’s find out what are the physical laws on which it is based.
Young and agile, Lorenzo Insigne is certainly the most loved Italian athlete of EURO2020. Thanks to dozens of memes that have gone viral on social media in recent weeks, the footballer is now considered a real star by the people of web. Why did the Neapolitan striker suddenly conquer such intense media fame?
An important role is certainly played by the colorful expressions in Neapolitan che Badge reserves to his opponents, especially on the occasion of particularly violent contrasts. The main reason, however, is to be found in his emblematic “tiraggir”, the unmistakable signature of the athlete.
For decency, we cannot report the Italian translations of the most famous quotes of the football player pronounced on the occasion of the EURO 2020. Nothing prevents us, however, from praising the most stand out physical peculiarities. Let’s analyze, in a “scientific” way, what makes the unmistakable shot of Badge an unrivaled masterpiece.
EURO2020: the art of “tiraggir”
Halfway between Holly’s right foot and Pirlo’s shot, the “tiraggir” (editor’s note from the Neapolitan, shot around) is the ace unlined by Badge in the opponent’s penalty area. Whether on a free kick or after a successful stop, it provides a precise dynamic.
After the skilful touch of the plate, the ball takes on a singular trajectory: spinning in a whirling way, it makes a deviated parabolic path (in the jargon called “effect”). If well set up, the attack is difficult to manage by the opponent’s extreme defender, precisely because of his unpredictability.
What is the basis of the physics of “tiraggir”?
The soccer ball used during the matches of EURO2020 has a mass between 410 e 450 grams. The circumference, on the other hand, oscillates between 68 e i 70 centimeters. In light of these measures, consider the ball as “material point”- that is, as a body endowed with pulp but negligible in size – it might be too simplistic. Let’s define it, therefore, a rigid body. To describe how the ball arrives near the goal, we must consider the superimposition of two motions: the motion of the center of mass and the rotational motion with respect to the axis passing through the center of mass.
The first performed by the balloon is quite similar to the parabolic motion. The two-dimensional parabolic motion can in turn be defined as the sum of two others. For clarity, we introduce a reference system. Let’s consider how “abscissa axis “ (x) the axis parallel to the field, with a positive direction facing the opponent’s goal. Of course, theordinate axis (y) will be perpendicular to the feet of Badge, with positive direction towards the sky. The ball is, at the moment it is kicked (at time t0), positioned at theorigin of the axes.
As it approaches the goal, the ball performs a accelerated rectilinear motion compared tosit there it’s a uniform rectilinear motion with respect to the x axis. Due to the presence of the famous “effect”, the dashed parabola is slightly “inclined” with respect to the third dimension, not yet mentioned for greater order. This is what makes the “tiraggir” done correctly, a difficult attack to parry.
Let’s not forget that the ball approaches the opponent’s goal rotating with respect to its axis! This aspect is physically very relevant, but let’s go step by step. For simplicity, let’s assume that the rotation speed under these conditions (called angular velocity) remains constant in modulo, also the center of rotation (pole) turns out to be fixed.
The first factor of the “tiraggir”, protagonist of EURO2020: the total moment of forces.
Fundamental requirements of the perfect “tiraggir” are the constant maintenance of rotational motion of the balloon and the inclination of the trajectory after the maximum of “inclined” parabolic motion. In order for the first condition not to fail, it is necessary to keep the total moment of the forces applied to the balloon. To ensure this, the point of application of the resulting force never corresponds to the center of rotation of the body (in that case we would have null arm). Or, if this unfortunately happens, the pole speed it must not be parallel to the total momentum of the system. Furthermore, Badge, to ensure the desired trajectory, shoot flat and off the tip. This allows, at the slightest expense of strength, greater precision.
The “tiraggir” and the Bernoulli equation: the couple you don’t expect
The real challenge is, however, to ensure the trajectory change after the maximum. As already mentioned, in this phenomenon an important role is played by the rotary motorbike. To justify this, the concept of lift. Put simply, it is there thrust that a moving object in a fluid receives as a result of pressure difference between the lower and upper surfaces. To understand its importance, just think that this is the “force” that allows planes to take off. According to the famous Bernoulli equation, a change of pressure involves a change in the sliding speed of the fluid.
The balloon moves in the air (fluid), in turn in motion with respect to the ball. Suppose the latter rotates in Counterclockwise. Its rotation involves the appearance of resulting speeds different on its two sides. Why does this happen?
The answer is simple. On the side where the scrolling speed of the air and the rotation speed of the balloon have the same direction, the two vectors are agree. For this reason, the two intensities do add up to give the resulting velocity vector. On the other, however, we will have two speeds disagree and therefore surely the intensity of the resulting vector will be more low of the previous one.
Thanks to this difference in “thrust” lateral, the ball “deforms” and its trajectory results inclined (to “effect”). How to manage it? Through a skilful control of the rotation of the ball, a clear consequence of the player’s experience.
At the end of this analysis we discovered that, in reality, the two fundamental requirements of the perfect “tiraggir”, the undisputed symbol of EURO2020, are both closely related to the rotational motion of the balloon. We hope that, even during this last and decisive match, Insigne will still be able to tame the laws of physics, without exaggerating with his colorful expletives.