In this article we will discuss about particle and system of particles. The study of system of particles is necessary to understand the concept of rotational motion. To understand system of particles, first we have to understand the meaning of a particle.
What do you mean by a particle?
A particle is defined as an object whose mass is finite but whose size and internal structure can be neglected.
What do you mean by system of particles?
A system is a collection of a very large number of particles which mutually interact with one another. A body of finite size can be regarded as a system because it is composed of a large number of particles interacting with one another.
Some Important Points Regarding System of Particles
Internal forces:
The mutual forces exerted by the particles of a system on one another are called internal forces. These forces are responsible for holding together the particles as a single object.
External forces:
The outside force exerted on an object by any external agency is called an external force. Such a force changes the velocity of an object.