| Astrophysics (Index) | About |
An inertial reference frame is a frame of reference, e.g., set of coordinates, moving (or not) such that any object with no net forces on it is not accelerating, basically a frame of reference moving at constant speed, i.e., that is not itself accelerating. An example of something else (i.e., a non-inertial reference frame) is one that is rotating, e.g., a reference frame indicating one's position on Earth, which is rotating, thus, in which "standing still" on the surface actually includes a slight acceleration toward the central axis. One can sometimes carry out dynamics calculations within such a non-inertial reference frame by pretending the existence of forces (fictitious forces) that would explain the consequences of the frame's acceleration, examples of such fictitious forces being (in the case of a rotating frame) centrifugal force and the Coriolis force.