Editing Speed (section)

===Average speed===
[[File:20230703 Average speed of bowling ball versus travel time.svg |thumb |As an example, a bowling ball's speed when first released will be above its average speed, and after decelerating because of friction, its speed when reaching the pins will be below its average speed.]]
Different from instantaneous speed, ''average speed'' is defined as the total distance covered divided by the time interval. For example, if a distance of 80 kilometres is driven in 1 hour, the average speed is 80 kilometres per hour. Likewise, if 320 kilometres are travelled in 4 hours, the average speed is also 80 kilometres per hour. When a distance in kilometres (km) is divided by a time in hours (h), the result is in kilometres per hour (km/h).

Average speed does not describe the speed variations that may have taken place during shorter time intervals (as it is the entire distance covered divided by the total time of travel), and so average speed is often quite different from a value of instantaneous speed.<ref name="Hewitt 2007, p. 42" /> If the average speed and the time of travel are known, the distance travelled can be calculated by rearranging the definition to
<math display="block">d = \boldsymbol{\bar{v}}t\,.</math>

Using this equation for an average speed of 80 kilometres per hour on a 4-hour trip, the distance covered is found to be 320 kilometres.

Expressed in graphical language, the [[slope]] of a [[tangent line]] at any point of a distance-time graph is the instantaneous speed at this point, while the slope of a [[chord (geometry)|chord line]] of the same graph is the average speed during the time interval covered by the chord. Average speed of an object is
Vav = s÷t