Speed and Velocity

Speed and Velocity

Speed is how fast something is moving.

Velocity is speed with a direction.

 

Saying Ariel the Dog runs at 9 km/h is a speed.

But saying he runs 9 km/h Westwards is a velocity.

 

  Speed Velocity
Has: magnitude magnitude and direction
Example: 60 km/h 60 km/h North
Example: 5 m/s 5 m/s upwards

Imagine something moving back and forth very fast: it has a high speed, but a low (or zero) velocity.

Speed

Speed is measured as distance traveled per unit of time.

Speed =  Distance
Time

 

Example: A car travels 50 km in one hour.

Its average speed is 50 km per hour (50 km/h)

 

Speed = Distance = 50 km
Time 1 hour

Example: You run 160 m, and it takes you 80 seconds.

You have run at a speed of 160 m per 80 seconds

Speed = Distance = 160 m = 2 m
Time 80 seconds 1 second

So, 160 meters in 80 seconds is a speed of 2 meters per second (2 m/s)

Velocity

Velocity is actually a vector:

It has magnitude and direction