náraz

Náraz is a Czech noun that denotes an abrupt contact or impact between bodies, or a sudden outward force. In everyday language it can refer to a collision or a blow, as in a car náraz into a barrier, or a hammer strike. The term is also used for transient, high-intensity forces in natural processes, for example náraz větru (gust of wind) or nárazová vlna (surging wave).

In physics and engineering, náraz describes an impact event and the associated transfer of momentum and energy. Nárazová zátěž or nárazový test means applying a short, high-load impulse to materials, joints or structures to assess strength and durability. The effects of a náraz depend on the velocity, angle of incidence, duration of the force, and the material properties involved; outcomes can include deformation, cracking or fracture. To mitigate damage, structures may be designed to absorb náraz energy, as in crumple zones on vehicles.

In everyday and technical usage, the word also appears in figurative expressions such as náraz do rozpočtu (an abrupt hit to the budget) or nárazová situace (a sudden disturbance). The adjective nárazový describes related phenomena: nárazový vítr (gust of wind) or nárazová zátěž (shock load).