Answer:
For the aceleration we have:
V = Vi + a * t
Being:
V = 20 m/s
Vi = 14 m/s
a = ?
t = 30 s
Then, lets replace acording the formula:
20 m/s = 14 m/s + a * 30 s
Clear "a":
a = (20 m/s - 14 m/s) / 30 s
a = (6 m/s) / 30 s
a = 0,2 m/s²
The aceleration of the car is 0,2 meters per second squared.