Speed

Speed is the

Knowing the distance travelled and the time an object took to travel the distance allows to calculate the object's average speed with the equation: vav = Δd/Δt

• vav =  average speed

• Δd = distance travelled

• Δt = change in time

Both distance and speed are scalar quantities, a physical quantity that's utterly described by its magnitude (some others are density, energy, mass, and time).

The following section shows how to use the equation to find the object's average speed.

Example 1

A dog runs in a straight line of 43m in 28s. What's his average speed?

• 43m = Δd

• 28s = Δt

vav =  43 / 28

vav =  1.54 m/s is the dog's average speed?