удар

• Each impact of a molecule with (or on) a wall of the container ...

• The impact of the fluid may either tend to close or open the valve.

• Meteoric impacts (or hits) upon the skin of a rocket ...

• Radioactive dust particles ... collected by impaction against the adhesive surface ...

• Leaky valves often result from pounding of valves against their seats.

• A hammer blow on hard rock ...