Free-falling vs Fermi-Walker

[emma83]

What is the difference between a free-falling frame and a Fermi-Walker frame ?

 

[atyy]

Fermi-Walker is free-falling if the path is free-falling. But Fermi-Walker can also be constructed for an time-like worldline.

 

[Entropia]

A free-falling frame and a Fermi-Walker frame are two different reference frames used in the study of general relativity. The main difference between the two is that a free-falling frame is an inertial frame, while a Fermi-Walker frame is a non-inertial frame.

In a free-falling frame, an object is in a state of free-fall due to the influence of gravity. This means that the object is not experiencing any external forces and is following a geodesic, or the shortest path in curved spacetime. In this frame, the laws of physics hold true and no additional forces are needed to explain the motion of objects.

On the other hand, a Fermi-Walker frame is a non-inertial frame that takes into account the effects of gravity and rotation. In this frame, objects do experience external forces due to the curvature of spacetime caused by the presence of massive objects. These forces are known as fictitious forces and are needed to accurately describe the motion of objects in a non-inertial frame.

In summary, the main difference between a free-falling frame and a Fermi-Walker frame is the presence of external forces. In a free-falling frame, no external forces are present, while in a Fermi-Walker frame, fictitious forces are needed to account for the effects of gravity and rotation. Both frames have their own uses in the study of general relativity and can provide valuable insights into the behavior of objects in curved spacetime.