törmäys

Törmäys is a Finnish noun meaning collision or impact. It is used to describe the moment when two or more objects come into contact because of relative motion, producing a force over a short time. The term is common in everyday language as well as in technical contexts, including road traffic, physics, and engineering.

In physics, a törmäys denotes the interaction between bodies that changes their motion. Collisions are analyzed in terms of momentum transfer and energy transformation. They are typically classified as elastic, where kinetic energy is preserved, and inelastic, where some energy is converted to deformation, heat, or sound. A perfectly inelastic collision is one in which the bodies combine and move together after impact. The coefficient of restitution quantifies elasticity, with 1 for a perfectly elastic collision and 0 for a perfectly inelastic one.

In everyday usage, the term covers traffic crashes (car, bicycle, or pedestrian impacts), mechanical impacts in engineering, and even astronomical or particle interactions described in simplified terms as collisions.

In road safety, preventive measures such as seat belts, airbags, crumple zones, anti-lock braking systems, speed limits, and safe road design aim to reduce both the likelihood of a törmäys and its severity. Research and accident investigations use data from sensors, scene analyses, and computer simulations to understand causes and improve safety.