A rigid body is an object consisting of many particles. When the term rigid body is used, it means that the particles within in the body itself are not subject to their own individual motion outside the motion of the rigid body. This is known as rigid body dynamics. In reality, sometimes you would have to do more than just consider the rigid body dynamics of an object, but instead you would need to study how an object vibrates. This however, will not be discussed in this section.
There are three basic types of rigid body motion. They are translational motion, rotation about a fixed axis, and general plane motion.