kollisioner

Kollisioner is the plural form of kollision in several Nordic and Germanic languages, referring to events in which two or more bodies exert forces on each other over a short time, producing changes in motion. They can occur through direct contact or via forces acting at a distance, such as gravity or electromagnetism. In classical mechanics these events are analyzed using conservation laws: total momentum is conserved in closed systems, and kinetic energy is conserved only in elastic collisions.

Kollisioner are classified by how much kinetic energy is preserved. In elastic collisions, kinetic energy is conserved in addition to momentum. Inelastic collisions involve some loss of kinetic energy, which is transformed into deformation, heat, or sound. A perfectly inelastic collision is a special case where the colliding bodies stick together after impact. Key quantities used to describe collisions include impulse (the change in momentum) and the coefficient of restitution, e, which ranges from 0 (perfectly inelastic) to 1 (perfectly elastic).

On a microscopic scale, collisions between particles underpin the behavior of gases and the rates of chemical reactions. Collision theory links kinetic energy, molecular orientation, and activation energy to the likelihood of reactions proceeding. Real-world examples include automobile crashes (inelastic collisions), hits in billiards (nearly elastic in idealized models), and astrophysical events such as galaxy collisions driven by gravity.

Studying kollisioner informs safety design, material science, and computational simulations in physics and chemistry.