In this lesson, we will begin by learning two terms, vector and scalar. A
scalar is simply a quantity (magnitude) i.e. ( 5 seconds, 6 meters, 24 Newtons,
etc. ). A vector on the other hand, has both magnitude and direction i.e. ( 6
meters east ). In physics, there are numerous different times when vectors are
useful. For instance, when working with various types of motion or forces.
In this first lesson, we will learn how to add horizontal or vertical vectors.
Let's start with horizontal. Think of a number line ranging from -10m to 10m,
with West being off to the left and East being towards the right.
If you want to add vectors, simply follow the number line. For example,
add 3m West and 7m East. What do you get?
Of course, you get 4m East! Good Job! All you have to do is repeat this number line procedure for adding vectors, no matter how many you have.
Now for vertical vectors. These are basically the same as horizontal
vectors, but instead of using East and West, we use North and South. (picture
at right). Just follow the number line like before to come up with your answer.
Add 5m North and 8m South. (picture at left). Naturally, you get 3m South.
Another way to add vectors, besides using the number line method, is to
think of North and East as positive (+), and South and West as negative (-) and
then just put them together using normal arithmetic. Be careful, though, not to
mix up your directions. You can't have a resultant vector going East when the
original ones were going North and South.
In the next lesson you will learn how to add
vectors of various angles.
