**Speed** is the rate of change of distance with respect to time. The symbol for speed is V and the base units for speed in the metric system is [m/s]

**Velocity** is the vector "equivalent" of speed. The velocity of a moving object is the speed the object travels in one particular direction.

The symbol for velocity is .

**Example** To indicate the velocity of a transport truck going at a speed of 100 km/h to Montreal (in an easterly direction) you would write

= 100 km/h [E] ---> this is the velocity of the truck!

To calculate the average speed (or average velocity) of an object we use the general equation

**Example:**

If you are walking with your dog in the park at 30 cm/s. How far will you have traveled in 20 minutes?

[tip: don't forget to change units from cm/s to m/s and minutes into seconds]

[tip: when you're asked to find "how far" it means ... "find the distance"]

**Given:** v_{av} = 30 cm/s = 0.30 m/s

t _{tot }= 20 min = 20 min X 60 s/min = 1200 s

**Find:** **d _{tot} ** --> use the above equation for v

_{av}but rearrange it so that you can solve for d

_{tot }

**Solution:**

d_{tot} = 0.30 m/s X 1200 s = 360 m

Therefore you and the dog would have walked a total distance of 360 m