Once you have the reference point you can then establish that
something has moved.  The
distance it compared to the reference
point is the amount of motion.  
Hint:
Distance is measured in meters
Now that we know how far something has moved compared to a reference point we next need to
know how long it took (time) to move.  From this we can get speed. (
speed = distance / time)
To find the average speed of
an object we just take the
total distance it covered and
divide by the
total time it
traveled.

The car at the left stops at
some lights and a stop sign,
so sometimes it is standing
still, but its average speed is
25 miles / hour.
Remember: We can use any units for distance (miles, meters, inches, cm, km, etc.) and any
distance for time (minutes, seconds, hours, years, centuries).  In our class we will normally be using
cm/sec due to the size of the room and the speed that most of my toys move.

Also remember: When you label the number for speed you must label it in the units you used. (if
you measured meters and seconds then it will be meters/sec.)
Chapter 12 - Matter in Motion - Speed