With what acceleration does the car brake if its speed has changed from 0.8 m / s to 0.2 m / s in 2 s?

Given:

u0 = 0.8 meters per second – initial vehicle speed;

u1 = 0.2 meters per second – vehicle speed over time interval t;

t = 2 seconds – time span.

It is required to determine a (meter per second squared) – the acceleration with which the car brakes.

To determine the acceleration of a car, you must use the following relationship:

(u1 – u0) / a = t, from here we find that:

a = (u1 – u0) / t;

a = (0.2 – 0.8) / 2 = -0.6 / 2 = -0.3 meters per second squared.

Answer: The car decelerates at an acceleration of -0.3 meters per second squared.