Speed and speed are terms used synonymously to refer to the relationship between the distance traveled and the time taken to cover it.
However, not in all cases speed and speed refer to the same thing. In more specialized fields, such as physics, they have slight differences.
The speed refers to the distance traveled by a object in a time determined. Since this is calculated by taking the distance traveled and dividing it by time, speed is a scalar quantity .
Instead, velocity refers to the length of time it takes for an object to travel in a certain direction . By involving the direction or sense of motion, velocity is a vector quantity .
Speed  Speed  

Definition  It is a scalar quantity that represents a distance traveled by a body in a given time.  It is a vector quantity that represents the displacement of a body in a time interval. 
Characteristics 


Calculation  Speed = distance traveled / time elapsed.  Speed = displacement / elapsed time. 
Media  It is obtained by dividing the distance traveled by the elapsed time.  It is obtained by dividing the displacement by the elapsed time. 
Magnitude  Scalar: described only with the use of numerical units.  Vectorial: it is described with the use of numerical units and the direction. 
Index
What is speed?
The speed indicates the relationship between the distance traveled by an object and the time that this used to cover it . As such, it can be measured in meters, kilometers, miles or knots (in the aquatic environment), per hour or per second.
Since speed is expressed according to distance and time, it is characterized by being a scalar quantity , which means that only numerical units are used to describe speed .
Since speed involves covering a distance during an interval of time, it can only give a positive value .
Speed characteristics
 Consider the distance traveled and the time elapsed.
 It is a scalar quantity.
 The average speed results from the division between the distance and a time interval.
 It is always positive.
Medium speed
Average speed refers to the total distance traveled during a given time.
For example, when Usain Bolt set the world record for the 100 meter dash in 9.58 seconds, his average speed was 10.44 meters per second.
What is speed?
The rate expresses the ratio between the distance traveled by an object and the time it takes you to cross it towards a direction specific.
Basically, velocity refers to the positional change of an object, from an initial reference point, towards the place to which this object has moved (the end point of the movement), and the time it has taken to do so.
Since it is a quantity that also determines the direction in which the displacement occurs , speed is considered a vector quantity .
Speed is measured in meters per second (m / s, according to the International System of Units), by direction.
In this sense, for an object to have a constant speed, it must travel in a constant direction for a certain amount of time. Any change in direction will imply variations in speed.
Speed characteristics
 Consider changing the position of an object in a specific direction.
 It is a vector magnitude.
 Average velocity involves the displacement between the time interval.
 You can give a positive, negative, or even null (zero) value.
Average speed
Average velocity is the displacement of an object from one position to another in a given time.
Since velocity takes displacement into account, if an object is in the same position after a specified time interval, its velocity is zero (zero) . In the same way, this magnitude can even be negative .
Learn more about the Difference between distance and displacement .
Speed and speed example
An example to better understand the difference between speed and speed would be the following: if an object is moving north at 100 kilometers per hour for one hour, it will have a speed of 100 km / h north .
On the other hand, if instead of going north it follows a circular path at 100 km / h for an hour, ending at the same point where it started, then we will say that its speed has been zero , although with this object it had a speed of 100 km / h .
The speed, then, would be the scalar absolute value of the speed. In this sense, if there is no direction or heading, we will be talking about speed, while if a direction is followed, then it will be about speed.
You may be interested in knowing about Scalar and Vector Magnitude