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Speed Vs Velocity 

Speed 

    Speed is the rate of motion, or the rate of change of position. It is expressed as distance moved (d) per unit of time(t). Speed is a scalar quantity with dimensions distance/time. Speed is measured in the same physical units of measurement as velocity.

Here are some examples of speed:

For human beings, an average walking speed is about 3 mph (~5 km/h, 1.39m/s), 
The speed of long distance jogging for average persons is about 6 mph (~10 km/h, 2.7 m/s).
Top athletic sprinters can run at 23.03 mph (~36.85 km/h, 10.24 m/s) within a short distance such as a 200 meters dash. 
Cycling can average 12 mph (~20 km/h, 5.56 m/s) 
Car can average 65 mph (~104 km/h, 28.9 m/s ) on highway 

Definition Provided by Edinfomatics.com 

Velocity

      Velocity: The rate in which an objects position is changing.  Mathematically is the change in position divided by the time in which the position is changed. 

    An Alternative definition of velocity is displacement divided by time.  Because displacement IS the change in an objects position, this definition is the same. 

   Velocity is also a Vector, meaning that IT MUST have a magnitude (size) and a direction. The magnitude of velocity is speed, so velocity has also been called speed with direction. 

Speed Vs Velocity

  Speed is measured in the same physical units of measurement as velocity. but does not contain an element of direction. Speed is thus the magnitude component of velocity. Velocity contains both the magnitude (speed) and direction components.