In the initial collision which begins the reaction, the particles must approach closely enough so that the short range strong force can affect them.

After the initial collision, the debris undergoes further collisions in a process called a collisional cascade.

This usually keeps the AIs in front clear of the initial pack-induced collision damage, which gives them another advantage.

The initial collision would shatter the enemy formation, and then the Germans could be overpowered in the ensuing melee.

But Williams said all the injuries could be traced to the initial collision.

The ship lost cabin electrical power shortly after the initial collision.

Thus there is uncertainty in the prevailing conditions at the initial collisions.

The impact of the initial collision threw the combatants apart.

Collisions after the initial collision may occur from the side where the car is more vulnerable.

But by then - at about 10.30pm and an hour after the initial collision - vital time had already been lost.