What is the restitution coefficient?

2 The coefficient of restitution, which is determined by experimentation, measures essentially rock. If the coefficient is close to one, the collision is elastic and bouncing, if it is close to zero, then the collision is more plastic. Most professional sports have specific instructions for the reconstruction coefficient such as balls, clubs and missiles. The restitution formula coefficient for objects that collide is defined as E = (v2-V1)/(U1-U2), where U1, U2 are speeds before collision and v1, v2 are speeds after the collision of each object. To determine the KOR object, it fell to a stationary object, such as a floor or table, a formula is e = √ (reflection / drop height). The speeds of objects moving horizontally or oblique can be difficult to measure.

KOR can also be considered a proportion of kinetic energy detained by two objects before and after collision. If the coefficient is close to one, the collision is very elastic, like a table tennis ballHe fell on the table made of stainless steel, which COR is 0.92. Most of the kinetic energy present before the collision remains as a kinetic energy after a collision. If the coefficient is close to zero, then there is a collision of more plastic, such as a piece of clay falling on a wooden table; Hlin holds without jumping. The kinetic energy was transformed into sound and other forms of energy and distorted clay.

Bounciness of Balls is a very important concept in sport, because more spring materials could give athletes an advantage. Since 1998, the United States Association, Golf Association has reduced the coefficient of restitution of golf clubs with standard golf balls to 0.83. The synthetic ball of the National Basketball Association and the hard linoleum of the floor is 0.79; However, this number may have an impact on temperature, air pressure and other factors.

In addition to giving players an unfair advantage, sports equipment that has unusually high restitution coefficients can be dangerous. For example, composite bats are bouncing thanWooden bats when hit by baseball. The balls affected by composite bats can have unexpectedly high speeds and lead to players injury. In May 2009, the National College Athletic Association adopted a restitution coefficient (BBCOR) as a means for better testing the performance of a baseball bat. All bats must have BBCOR less than 0.500.