# Progressive and retrograde movement

The movements will be called progressive or retrograde according to their sense in relation to a starting point.

In the study of uniform motion , there is the determination of the position hourly function, an equation that provides the position in which a mobile will be found after a certain time interval. The position time function for uniform motion is given by:

**s = s _{0} + vt**

**s** : End position;

**s **_{0}** :** Starting position;

**v** : Speed;

**t:** Time instant.

Furniture movements always follow an orientation, following a numbered line that will indicate the direction of increasing and decreasing positions. As an example, we can mention the mileage indicator plates on the highways that show the driver what is the position occupied by him in relation to a point of origin called the starting point. If the driver moves away from the starting point, the values of his position increase; but if it approaches the zero point, its position values decrease.

**progressive movement**

The movement of a piece of furniture will be classified as progressive if its speed is in the same direction as the growth of position values. In this case, the velocity will be considered a number greater than zero (v > 0).

Therefore, the position time function should be used as: **s = s **_{0}** + vt**

Since the hourly function of uniform motion is a function of the first degree , the graph for progressive motion is an ascending line.

**retrograde movement**

The movement of a bile will be classified as retrograde if its velocity is in the opposite direction to the growth of positions. In this case, the velocity will be considered a number less than zero ( **v < 0** ).

Therefore, the position time function should be used as: **s = s **_{0 –}** vt**

Since the hourly function of uniform motion is a function of the first degree , the graph for retrograde motion is a descending line.