Inertial System

From bio-physics-wiki

Jump to: navigation, search

An inertial system is a system with an inertial frame of reference in which Newton's laws are valid. For example if a body rests in an inertial system, it continues to rest for all times. In a non-inertial system this is not true. Take for example a system $S$ that accelerates with $a$ relative to an inertial system. From the perspective of system $S$ a particle that rests in the inertial system would accelerate with $-a$. An observer in the $S$ system would have to introduce a fictitious force $F_{fict.}$ that explains, why the particle accelerates. Without fictitious forces Newton's first law would not hold in $S$, since a body at rest does not continue to rest. Therefore $S$ is no inertial system.

Intertialsys.png

In an inertial system space is homogeneous and isotropic, furthermore time is homogeneous. More details on these properties can be found in the article on the Galilean Transformation.