Average Speed: Formulas and Exercises Solved

The result between the time traveled and the time taken to make the route is called average speed.

In the international system of units, the unit stops average speed is the meter per second (m/s). The most common is kilometer per hour (km/h) used for cars, motorcycles and other vehicles.

Unit transformation

Example:

72 km/h (split) 3.6 = 20 m/s

40 m/s x 3.6 = 144 km/h

Factor 3.6 is because 1 k = 1000 m and 1 h = 3600 s.

To change 1 km/h to m/s the factor 3.6 will appear dividing the equation. If the situation were reversed, it would appear multiplying.

Average speed is not average speed

THE average speed of a body is not the result of the arithmetic average of the speeds that are reached during a course.

It is the value corresponding to the constant speed to be able to travel a path in a given time.

Example

Let's say you travel with your car and arrive at 10 km at your final destination. Imagine that the first half of the path has been made at a speed of 40 m/s and the second half of this path is covered at 30 m/s.

So what would be the average speed of your trip?

We are led to assume that the average speed it would be the arithmetic mean between speeds 30 and 40 m/s.

But this value is wrong because the average speed it is not speed average.

The right way to solve this exercise would be to determine the time spent on each half of the journey and then set the average speed.

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The formula

The formula is V= d/t where V equals the average speed, d equals the total distance and t equals the total time.

Exercise solved