How many position coordinates are required to identify the position of a system undergoing one-dimensional motion? what symbol should use to identify systems position and one-dimensional motion?

One-dimensional motion can be plotted through the Cartesian plane which has a coordinates of (x,y). These coordinates are the abscissa and ordinates. Since, there are two coordinates, the answer to the second item is two.

The symbol that can be used to identify systems position is (x,y). Since this is one dimensional motion, it is possible that one of the two coordinates becomes zero.