inertial frame

Choosing a frame of reference requires deciding where the object’s initial position is and which direction will be considered positive. Valid frames of reference can differ from each other by moving relative to one another. Frames of reference are particularly important when describing an object’s displacement.

A coordinate system attached to the Earth is not an inertial reference frame because the Earth rotates and is accelerated with respect to the Sun.

A “frame of reference” is a standard relative to which motion and rest may be measured; any set of points or objects that are at rest relative to one another enables us, in principle, to describe the relative motions of bodies.

If a particle moves on a straight line and no force is applied, the reference frame is inertial. Since there is a finite number of known forces, one can in principle rule out each of them and reduce to a situation where no force is applied to the particle.

Earth is an Inertial Reference Frame as it revolves around the Sun at a constant velocity. But Earth rotating and at the same time revolving at a constant velocity is also due to a centripetal acceleration. So we can conclude that Earth in accordance with Sun is a Non Inertial Reference Frame.

Why is the centrifugal force the ladybug feels in the rotating frame called a fictitious force? It is a result of rotation. It is not part of an interaction between two objects.

Centrifugal force is an outward force apparent in a rotating reference frame. It does not exist when a system is described relative to an inertial frame of reference. When this choice is made, fictitious forces, including the centrifugal force, arise.

In order for things to work out in a non-intertial frame, a force needs to be added (a non-real force). This force is the centrifugal force. The centrifugal force is the force (non-real force) that is needed to make things work as you would think in a reference frame that is accelerating.

Centrifugal Force acts on every object moving in a circular path when viewed from a rotating frame of reference. Some examples of Centrifugal Force are given below. Weight of an object at the poles and on the equator. A bike making a turn. Vehicle driving around a curve.

Centripetal force is the force REQUIRED for circular motion. Centrifugal force is the force that makes something flee from the center.