III.1.6. Average acceleration.

Uniform rectilinear movement is possible in everyday life, only on small sections of the highway. In the case of real movements, the speed of the furniture increases or decreases over time, due to traffic lights, curves, pedestrian crossings, speed limits. All cars have an accelerator pedal and a brake pedal.

A mobile has an accelerated movement when its speed increases over time.

Here are the positions of a mobile at equal intervals in accelerated motion:

At start-up, the mobile has an accelerated movement, because its speed increases from zero.

Here are the positions of a mobile at equal intervals in the braked motion:

When stopped, the mobile has a slow motion, as its speed drops to zero.

The average acceleration (a_m sau a) is the physical parameter equal to the ratio between the variation of the speed (its increase or decrease) and the duration in which this variation occurred.

Characterization of average acceleration as physical parameter: