# Does the centrifugal force affect stationary objects as seen from the inertial reference frame?

If an object is moving at the same speed as a rotating/accelerating frame of reference it's in contact with but in the opposite direction (making its displacement zero), would such an object be subjected to the fictitious centrifugal force?. Considering the fact that the object's velocity vector isn't changing with time and the object appears stationary as viewed from the inertial frame of reference.

• – GCLL Mar 18 '16 at 23:30

Fictitious forces are introduced to make the time evolution of the system in the given reference frame predictable using the Newton's laws of motion. So, in a rotating frame fictitious forces are needed, as the observed motion is a circular motion of constant speed. In particular, you need the centrifugal force and the Coriolis force, which are both non zero. In an accelerated frame the observed motion is an accelerated one, and you need the appropriate $-m\vec{a}$ fictitious force also in this case. The fact that the velocity vector is not changing in the inertial frame is not relevant.