BELIEVE   ME   NOT!    - -     A   SKEPTIC's   GUIDE  

Rigid Bodies

Despite the fact that all Earthly matter is composed mostly of empty space sprinkled lightly with tiny bits of mass called atomic nuclei and even tinier bits called electrons, the forces between these bits are often so enormous that they hold the bits rigidly locked in a regular array called a solid. Within certain limits these arrays behave as if they were inseperable and perfectly rigid. It is therefore of some practical importance to develop a body of understanding of the behaviour of such rigid bodies under the influence of external forces. This is where the equations governing rotation come in.