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In support of all the students who are displaced from school due to the Corona virus. Access to physics zone and chemistry zone lessons are now available free of charge. This will be maintained at least through August 1st 2020. Learn and be well.

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Speed and Velocity

dinstance bug crawlingIn order to understand the difference between speed and velocity, you must first understand the difference between distance and displacement.  (visit that lesson if needed)


Speedspeed of a bug
The rate of change in distance with respect to time.   Since speed is built from distance, a scalar quantity, then speed is also a scalar quantity.  This means it carries no direction information with it.
speed formula
  (the bar indicates average and the delta means change)
Velocityvelocity bug
The rate of change in displacement with respect to time.  Since displacement is a vector quantity, then velocity is also a vector quantity.  It has both magnitude and direction.
 
This formula is considered the definition formula for average velocity.
Both speed and velocity are typically measured in units of miles per hour, kilometers per hour (Km/hr), or meters per second (m/s).
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