The Differences Between Speed And Velocity I Oxford Open Learning

# The Differences Between Speed And Velocity

### … And How Are They Applied In Real Life?

The words speed and velocity are often used interchangeably by the average layperson, (including me until I wrote this article). However, in actuality, speed and velocity do not represent the same thing.

Take speed for example; this measures how fast an object is travelling. It is the distance that an object travels relative to a unit of time. Speed can be measured in metres per second, kilometres per hour, or miles per hour. This simple equation explains Speed:

### Speed = Distance Travelled / Time taken

If a car travels 30 metres in 2 seconds, then its speed is 15 m/s:

30 m / 2 s = 15 m/s

Now, if we look at velocity, the only difference between velocity and speed is that velocity has a direction, which is represented by displacement in the equation below.

### Velocity = Displacement / Time

Displacement is the distance an object moves in a straight line or any specific direction away from the starting point. So, if we want to know the velocity of a car travelling 30 metres west in 2 seconds we would calculate it like this and the answer would be 30 m/s west.

30 m / 2 s = 15 m/s west

But what difference does this make? How are measures of speed and velocity applied differently in the real world? We all know how speed is used in the real world: it describes how fast a sports car goes, how fast Usain Bolt runs, or how fast the wind is blowing.

### How The Equation Helps Us

Velocity is a little more esoteric, but it has countless applications in every life that you probably didn’t know about. For example, while your car speedometer measures speed (it does not give a direction). The adjacent car Sat Nav measures the car’s velocity (rate of movement in any given direction) and accumulative changes in velocity to estimate and update travel time and provide accurate directions. If Sat Nat relied on a speedometer we’d soon be lost!

Aviation depends heavily on velocity metrics, with pilots and air traffic controllers relying heavily on such measurements to ensure coordinated take-offs and landings and to avoid air collisions. Airports would simply not be able to function without velocity measurements.

Engineers consider wind velocity when designing buildings and bridges to ensure they can withstand wind loads from all directions to remain standing in real-world conditions.

After considering just a few of these mission-critical examples of the real word difference between speed and velocity, I will never use these terms interchangeably again!

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I am a practising HR consultant working with several start-ups on an ongoing and ad-hoc basis in the London and M4 area, and am a Chartered Member of the Chartered Institute of Personnel and Development or CIPD. I am the Director of thecareercafe.co.uk; thecareercafe.co.uk is a resource for start-ups and small business. It includes a blog containing career advice, small business advice articles, HR software reviews, and contains great resources such as HR Productivity Apps.