Question

Pseudo force, also called fictitious force, such as centrifugal force, arises only in
(A.)Inertial frames
(B.)Non-inertial frames
(C.)Both inertial and non-inertial frames
(D.)Rigid frames

Answer 1

Hint: When a frame of reference moves with some acceleration, the object is assumed to experience some force acting on it. If we assume the referential frame at rest, objects would appear to move with the same magnitude of acceleration.

Complete step by step answer:
A pseudo force or fictitious force is a force that appears to act on a mass object whose motion is described and observed using a non-inertial frame of reference, such as an accelerating or rotating reference frame. The pseudo force arises due to an object’s inertia when the reference frame does not move inertially, and therefore it begins to accelerate relative to the free object. The fictitious force does not arise due to physical interaction between two bodies, such as other forces like contact force or electromagnetic force, but rather it arises from the acceleration of the non-inertial frame. If we view from the frame reference, the object would appear accelerating, and this requires some force acting on the object. This force is called the Pseudo force.

Using Newton’s second law of motion,

$F=ma$

Where,
$F$is the pseudo force acting on object viewed from a non-inertial frame
$m$is the mass of the object
$a$is the acceleration of non-inertial frame

The fictitious force on an object arises as an imaginary influence, rather than being a real force, when the frame of reference used to describe the motion of an object is accelerating as compared to an inertial frame. A frame can accelerate in any arbitrary direction; this means that the fictitious force can also be arbitrary directed.

Different types of fictitious forces can be:

(I)Fictitious force caused by any relative acceleration of the acceleration of the origin in a straight line, known as rectilinear acceleration.
(II)Fictitious force due to rotation of frame, called the Centrifugal force and Coriolis force.
(III)Fictitious force caused by a variable rate of rotation, known as Euler force.
(IV)Pseudo or fictitious force is observed only in non-inertial frames.
Hence, the correct option is B.

Note:
The pseudo force is an imaginary force that seems to be acting on an object being viewed from a non-inertial frame. If we take a frame of reference at rest, the object would appear to be moving with the same acceleration, though the direction would be opposite. The direction of pseudo force is opposite to the direction of acceleration of the frame of reference.