To locate the position in motion or at rest,we need a frame of reference.
Simplest way to choose a frame of reference is to choose three mutually perpendicular axis labelled as X-,Y- and Z- axis
as shown in figure below
More about Frame of reference
We know that we need a frame of reference is needed to locate the position of any object. For that we choose rectangular co-ordinate
of three mutually perpendicular axis that are $x$, $y$ and $z$ axis. The point of intersection of these three axes is called
and is considered as the Reference Point.
The $x$, $y$ and $z$ co-ordinates describe the position of object with respect to the co-ordinate system.
To measure time , we need a clock.
The co-ordinate system along with a clock constitutes a Frame of reference.
So , the frame of reference is a co-ordinate
system , with a clock w.r.t. which, an observer can describe the position, displacement etc. of an object.
Frames of reference are of two types:-
Non-Inertial frame of reference:- These are the frame of reference in which , Newton's first law of motion is not applicable
Such system of labelling position of an object is known as rectangular coordinates system
If A(x,y,z) be the position of any point in rectangular co-ordinates system it can be labelled as follows
Point O is the point of intersection of these mutually perpendicular axis and is known as reference point or origin
of frame of reference
To measure a time ,we can also attach a clock with this frame of reference
If any or all co-ordinates of the object under consideration changes with time in this frame of reference then the
object is said to be in a motion w.r.t the frame of the reference otherwise it is at rest
For describing motion in one dimension we need one set of co-ordinates axis i.e only one of X,Y and Z axis