### Chapter 1: Physics in Table Tennis

Table tennis is one of the most popular sports in the world; this sport is the second most complete after swimming, also, is so accessible and interesting that this sport is the second most practiced in the world. Table tennis is an awesome sport in which physics play an important role. It has developed so much that scientists are wondering how table tennis defies the gravity laws of Newton. This sport isn’t a contact sport as soccer or basket in which you can get hurt; but instead, in table tennis you can play a game with older people and this helps to gain experience. Table tennis games are very complex because of the spin, the Magnus effect and gravity play. These are the most important role in this sport.
Gravity plays a very big role in table tennis, it is more or less the 85% of this sport; scientific and NASA research said that table tennis is the most difficult sport to be practiced, also that the ball could reach more than 100 Km/h (“Table Tennis”). All of these studies are very controversial because there are many cases in which the ball passes down the net to the other part of the table with a ball of 3 grams of weight. The effect is diminished when given cut effect; these are the basic laws that explain how table tennis works. This generates a lot of advantages and disadvantages, for example in the coast there is more air, so the ball is less fast and there is more time to catch the ball and hit it; but also there are many factors that change the bounce of the ball as measure of the roof and the sea level(“ tt_physics_maths”).
The Magnus effect is basically the name of the physical phenomenon whereby the rotation of an object affects the same trajectory through a fluid. This effect is more noticed in pro competitions because top players are trained to beat the air so the Magnus effect that in this case is the topspin, backspin, and sidespin can be put into practice (“Magnus effect”); to have a good effect, in other words comply with the law of Magnus effect, it is extremely necessary to have a good rubber because of  the adherence of this material, “ The Magnus effect is often used to explain the commonly observed movements of spinning balls in sport, especially association football, table tennis, tennis, volleyball, golf, baseball, cricket and in various paintball marker brands. The effect also affects spinning missiles, and is used in rotor ships and Flettner aeroplanes (“Magnus effect”).
Spin is what table tennis is about. In a professional match everything is spin and the hit of the ball is almost never used, only in smashes; so to make a good spin is necessary to have many years of practice and also a good racquet. This could be complemented by seeing table tennis videos of top players. This spin makes the game more awesome because of the effects and curves, making the trajectory of the ball change, so instead the ball going out of the table it is a good ball and the opponent generally gets confused. To make this spins, there are many types of effects such as the cut effect, topspin, backspin, sidespin, side effect, death effect, an mixed ones as the cut side effects ("spin_in_tt").
Finally, Table tennis is a very interesting sport to be studied because of its lots of physical phenomena such as the most important, gravity which has been studied for  hundreds of years, and how this sport can defies many of its laws; the biggest studies of important associations as NASA and their positive and negative conclusions in table tennis players, also the role of Magnus effect which could explain the important role of air in this and many other sports; finally the spin, the complement of gravity and Magnus effect so without this table tennis couldn’t be as wonderful as it is.