Question

What is the difference between an inertial frame and a non-inertial frame?

Answer 1

As we all know that there no such thing as absolute , everything is relative to each other . For example , if I'm sitting on my chair in my room then according to me I'm at rest but as we all know that earth is always rotating about its own axis and revolving around sun , so according to a man from another planet who is looking at the rotating and revolving earth , I'm not at rest according to him .

So we can conclude the fact that there is no such thing as absolute everything is relative . Same applies with motion of bodies also , any motion is basically studied or analysed according to any reference . For example, mostly we study and solve kinematics problem with reference to earth .

So for studying any motion we need to have a frame of reference which can be easily defined as a set of standard values and axes and points relative to which any motion can be studied . Frame of reference is basically classified into two categories
1. Inertial Frame Of Reference
2. Non-Inertial Frame Of Reference

1. Inertial Frame Of Reference
This type of frame of reference is a frame which is non- accelerating in nature or zero acceleration or moving with constant velocity. For example mostly earth acts as an inertial Frame Of Reference as we consider it as at rest according to us and solve the problems with reference to it .

Also a general point can be said that the Newton's Laws are valid in inertial Frame Of Reference .

2. Non-Inertial Frame Of Reference
This type of frame of reference is a frame which is accelerating in nature .
For example if I'm moving in a train and studying the motion of a car moving parallel then I'm acting as a Non-Inertial Frame Of reference for the motion of car .

And in this frame of reference sometimes Newton's Laws of Motion are violated as law of inertia doesn't hold in it .