This is an inelastic collision. If kinetic energy before is the same as after, then the collision is elastic . Interactions between molecules are examples of perfectly elastic collisions.

The hydroxyl radical (OH) is one of the most interesting molecules in molecular dynamics. In particular, inelastic collisions of free radicals such as OH are profoundly important in environments ...

An example would be if you pushed one magnet toward another -- at just the right angle for them to stick together on contact -- and then they both started sliding together at half the speed of the ...