A car on the path of 200 m drops its speed from 30 m / s to 10 m / s. a) with what acceleration does the car move?

A car on the path of 200 m drops its speed from 30 m / s to 10 m / s. a) with what acceleration does the car move? b) how long did it take the car to cover the specified path? c) what is the average vehicle speed?

Given:
S = 200m
V0 = 30m / s
V = 10m / s

To find:
and-?
t-?
Vav-?

Decision:
t = S / (V0 + V) = 200m / (10m / s + 30m / s) = 200m / 40m / s = 5s
a = V-V0 / t = 10m / s-30m / s / 5s = -4m / s
– tells us that this is inhibition
Vav = S / t = 200m / 5s = 40m / s
Answer: -4m / s; 5c; 40m / s