Explain how to identify a starting position
on a line.

We can easily find out the beginning point of the line by using dot representation. When it comes to position vector, it expresses the exact position of certain object from the starting point of the coordinate system. The vector is a straight line that has a certain end which is fixed to its body

Displacement is defined as the distance, in any direction, of an object relative to the position of another object. Physicists use the concept of a position vector as a graphical tool to visualize displacements. A position vector expresses the position of an object from the origin of a coordinate system

Explanation:

so easy. just google the electromagnetic waves and it’ll pop up.