We explain what distance is in physics and mathematics, and how it is measured. Also, the relationship between distance and displacement.
What is distance?
Distance, in physics and mathematics, It is a scalar quantity that is measured in units of length and which can be understood as the path between a point of origin A and a destination point B. This path is normally equivalent to the length of a line that joins two points, being in a Euclidean plane.
The word distance comes from Latin distantmade up of the prefix dis- (“divergence” or “distance”) and the verb stare (“be”). That is why it is often used in everyday language to indicate, literally or metaphorically, the space or time that separates two events or two objects.
Distance is measured, according to the International System (SI) of weights and measures, in units of length called kilometers (km), or in its derived units: meters (m), centimeters (cm), millimeters (mm), etc
Distance and displacement
Do not confuse distance with displacement. The first is a scalar magnitude, for whose measurement units of length are enough, while displacement is a vector quantity. This difference means that its measurement, Unlike distance, it also involves a direction that is, a sense.
Both concepts can be differentiated if we think that the distance between point A and point B is the total length traveled when going from one to the other, while the displacement will only take into account the distance in a straight line between one and the other.
That is to say: suppose that between point A and point B there are 10 kilometers of separation, but that we decide to travel them in several turns, approaching point C and then another point D, instead of going in a straight line, we will have traveled a total amount of kilometers far greater than the 10 that would have been involved in walking in a straight line. That's our distance traveled.
However, we will have only traveled 10 kilometers, since for the calculation of the displacement the route is not of interest, but rather the start and end points.
References
- “Distance” on Wikipedia.
- “Displacement (vector)” on Wikipedia.
- “Distance” in the Dictionary of the language of the Royal Spanish Academy.
- “Difference between distance and displacement” in Digital Public School of the University of La Plata (Argentina).
- “Difference between distance and displacement” (video) in iEnciclotareas.
