# Q & A: What is a vector?

Q:
what is a vector
- raina (age 13)
chehalis washington usa
A:
The word 'vector' describes many different things in various fields of study.
See     for examples.
In physics, our expertise here, a vector is the description of a measurable quantity that may require  more than one number.  A good example of a one-dimensional vector, called a scalar in the jargon, is speed:  "I am driving my car at 50 miles per hour".    Related to that is 'velocity', which requires more numbers to completely describe the motion:  "I am driving my car at 50 miles per hour in the north-east direction" requires a two dimensional vector to completely specify the motion.   In an airplane you can be flying 200 miles an hour in the south west direction and descending at 1000 feet per minute.  That would be a 3-d vector.  And so on...

LeeH

One slightly more technical note: A vector isn't just any old list of numbers, like how many cats you have and how many dogs you have. The different parts of a vector have to represent basically the same sort of thing, like distances in different directions. You can describe how to get somewhere either by saying how far north/south and how far east/west or, if the streets in your town are laid out differently, by saying how far northeast/southwest and how far northwest/southeast.  You can't say what pets you have by saying how many cogs and how many dats. Mike W.

(published on 05/16/2013)