Question

Define inertial and non-inertial frame of reference. Give example

Answer 1

Hint: Frame of reference implies a reference with respect to which any measurement is done. Inertial frame implies the reference under the effect of inertia. Non inertial frame, on the other hand, implies the reference free of inertia.

Complete answer:
Inertia is the property of a body by the virtue of which it either remains at rest or in the state of motion until it is acted upon by any external force. Inertial frame of reference takes into account this property. Every body which is analyzed under an inertial frame of reference tends to maintain its position if rest or of motion until the body is acted upon by any external force. Thus, it can be said that an inertial frame of reference either remains at rest or moves with a constant velocity. For example, a car at standstill or a bus moving with constant speed are considered to be inertial frames of reference.

A non-inertial frame of reference is one which is in the state of acceleration. If a body seems to be not obeying the inertia rules, it can be said to be in a non-inertial frame of reference. In this frame of reference, Newton’s first law of motion does not hold true. The acceleration of a non-inertial frame is taken with respect to an inertial frame of reference. For example, if a car is moving with a certain acceleration it is said to be in a non-inertial frame of reference.

Note:
As long as the frame of reference is not moving or moving with a constant velocity it is termed as an inertial frame of reference. If the frame is accelerating or moving in a circular path with constant speed, it is termed as a non-inertial frame of reference.