Fictitious force
In physics, a fictitious force, also called a pseudo force, d'Alembert force or inertial force, is an apparent force that acts on all masses whose motion is described using a non-inertial frame of reference, such as a rotating reference frame.
Description
The force F does not arise from any physical interaction between two objects, but rather from the acceleration a of the non-inertial reference frame itself. As stated by Iro:
Such an additional force due to nonuniform relative motion of two reference frames is called a pseudo-force.
— H. Iro in A Modern Approach to Classical Mechanics p. 180
Assuming Newton's second law in the form F = ma, fictitious forces are always proportional to the mass m.
A fictitious force on an object arises when the frame of reference used to describe the object's motion is accelerating compared to a non-accelerating frame.
As a frame can accelerate in any arbitrary way, so can fictitious forces be as arbitrary (but only in direct response to the acceleration of the frame).
However, four fictitious forces are defined for frames accelerated in commonly occurring ways:
- One caused by any relative acceleration of the origin in a straight line (rectilinear acceleration)
- Two involving rotation:
- Centrifugal force
- Coriolis force
- One, the Euler force, caused by a variable rate of rotation, should that occur.
Gravitational force would also be a fictitious force based upon a field model in which particles distort spacetime due to their mass.
See also
External links
- Fictitious force @ Wikipedia
