[File:Flight dynamics with text.png|right|thumb|The position of a rigid body is determined by the position of its center of mass and by its
attitude (at least six parameters in total).]] In
physics, a
rigid body is an idealization of a solid
body in which
deformation is neglected. In other words, the
distance between any two given
points of a rigid body remains constant in time regardless of external
forces exerted on it. Even though such an object cannot physically exist due to
relativity, objects can normally be assumed to be perfectly rigid if they are not moving near the
speed of light.