## Distance traveled

Imagine we are traveling by car from Santurce to Bilbao. Before leaving we reset the odometer to zero. As we move forward on our way the odometer reading will increase its value until we arrive to Bilbao, where the odometer will show the distance traveled between the two cities (for example 22 km). The *length* of road, *measured over the trajectory*, is called **distance traveled**, or simply **distance**. This measurement is a scalar, and like any length, its **unit** in the International System (S.I.) is the **meter (m)**.

The **distance traveled**, $\u2206s$ is the * length* of the

**followed between the initial and final position of the body in motion.**

*trajectory*Distance Traveled

The distance traveled by a body, between two positions, is the length of the trajectory between those two positions, or what is the same, it is the difference of the distance traveled up to the last position (S_{2}) minus the distance traveled in the previous stretch (S_{1})

$$\Delta S={S}_{2}-{S}_{1}$$

In general, the calculation of the **distance traveled** is equivalent to the calculation of the length of the trajectory curve. This calculation is not immediate and requires mathematical tools which exceed the level in which we find ourselves. However, it is important to remember that, in the case of circular trajectories, the calculation of the distance traveled is equivalent to the calculation of the length of the circumference arc and that is given by:

Where:

*L*: Arc length- $\theta $ : Angle of the circumference arc in radians
*r*: Radius of the arc

Finally, remember that **the distance traveled is always positive**, since the length of the curve described by a moving body will always be a scalar greater than or equal to zero.