The car brakes so that in 5 seconds its speed decreases from 15m / s to 5m / s. Acceleration equals …?

t = 5 s. V0 = 15 m / s. V = 5 m / s. a -? According to the definition: the acceleration of a body is a vector quantity that shows how quickly the body’s speed changes. Acceleration a is defined as the ratio of the change in speed ΔV to the time t during which it occurred: a = (V – V) / t. a = (5 m / s – 15 m / s) / 5 s = – 2 m / s ^ 2. The sign “-” means that the acceleration is directed in the opposite direction to the speed of the body, the body is decelerated.
Answer: car acceleration a = 2 m / s ^ 2.