1. Scalars vs Vectors
Scalars – a quantity that only needs a magnitude (with a unit) to describe it
Ex:
Vectors – a quantity that needs a magnitude (with a unit) and a direction to completely describe it
and there are many others still to come…
So vectors are generic tools, developed specifically for Physics, used to help us solve physics problems and explain things more clearly.
You’ve never heard of them before because Bio & Chem only deal with scalar quantities, so your teachers never needed to mentioned there were also these things called vectors.

2. We use arrows to represent a vector quantity in a diagram
its length represents the magnitude of the vector, according to the units set by some scale
Choose a scale so that your diagram will be as large as possible in the space provided, but no arrow will need to be longer than your c-thru.
the arrow tip indicates its direction
according to some directional key
Try one: Draw the velocity v = 30 km/hr, East
What should we use as a scale?

3. So finally, v = 30 km/hr, east would look like:
scale 1 cm = 2 km/hr & key N
W E S
Note: the tip should be drawn very carefully so to not change the length of the carefully drawn arrow.
Now let’s look in the text at some more examples on page 29.

4. Vector Components
Consider the following: for a displacement of something that ends up SW of where it started, that could have come about by that object moving so far directly W, then so far directly S…
The legs of the right triangle are the components of the original vector

5. OR, for a plane that flies with a velocity in the NW direction, that could be because the plane’s engines where moving it W while the wind was blowing it N…
Again, the legs of the right triangle are the components of the original vector

6. they are vectors themselves they lie on the main directional axes
Sometimes in Physics (actually, quite often!) it is important to know the value of the components of a vector
there are 2 for each vector
they are vectors themselves
they lie on the main directional axes
they’re perpendicular to each other
if added together, their sum equals the original vector
The process of determining the components of a given vector is called resolution, or, another way, to resolve the vector into its components.
Let’s try one….