Do you know the position where God proclaimed that let there be Universe?

Hi Guys

A particle is a point mass. To study its motion we must know its position with respect to a desired point  in one dimension (1D) along a straight line , or two intersecting lines ( axes ) forming plane in 2D or three intersecting lines (axes) forming space in 3D.

Rene desCartes (1596-1650) invented the method of studying Geometry using Algebra by defining Co-ordinate System.

In 2D plane ( an ant be crawling on a floor ) you need two intersecting lines to determine the position of the ant uniquely, called axes. The point of intersection is called origin and the distances of the point from the axes gives us an ordered pair (a,b) called the co-ordinates. desCartes made it easier by considering the axes to be orthogonal ( mutually perpendicular ) and there evolved the analytical geometry with rectangular cartesian system. You know graphs, so you have some idea about it.

Here the ordered pair (x,y) are the coordinates where x is the distance from Y-axis called abscissa or X-coordinate and y is the distance from X-axis called ordinate or Y-coordinate. Thus the coordinates of origin is (0,0).

Identically for 3D space ( a mosquito by flying in that room ) we need another coordinate - distance of the point from floor (XY-plane) called Z-coordinate

and we get a point in space as an ordered triad (x,y,z).

You may understand easily the difference between 3D and 2D as the flying mosquito in the room and the shadow of the mosquito on the floor.

Now I give you something to think on :

Can a particle be at two or more positions at an instant of time?

or,  if a particle changes its position will there be a finite time elapsed during its motion?

So now you see that to study motion we must know the Coordinate Geometry well.

All the best. You are ready now to get into the realms of Physics...