Understand that, for many purposes, a system can be treated as a point-like particle with its mass concentrated at the center of mass. a complex system of objects, both point-like and extended ones, can often be treated as a point particle, located at the system's center of mass. such an approach can greatly simplify problem solving.

Treating the system as a point-like particle allows us to assign a quantity to the object and monitor this quantity throughout any changes. The complexity of the system which includes geometry, appearance, and extensions can complicate the studying of the system.

This is what i found on google “according to the collision theory, the following criteria must be met in order for a chemical reaction to occur: molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. molecules must collide with the proper orientation.” i hope this information you.