During which type of collision do the two objects stick together

Perfectly inelastic collision

Explanation:

There are two types of collisions:

- Elastic collision: in an elastic collision, the total momentum of the objects before and after the collision is conserved; also, the total kinetic energy of the objects before and after the collision is conserved.

- Inelastic collision: in an inelastic collision, the total momentum of the objects before and after the collision is conserved, while the total kinetic energy is not. In fact, part of the total kinetic energy of the objects is lost during the collision, converted mainly into thermal energy (or other forms of energy) due to the presence of frictional forces.

- A particular type of inelastic collision is called perfectly inelastic collision: this occurs when the two objects stick together after the collision. In this case, the maximum amount of kinetic energy of the system is lost.