Answer:
You are given a system of constant acceleration with initial & final speeds, along with the time interval in between. The acceleration is calculated as:
A = delta-V / delta-T = (change in speed during acceleration) / (time duration of acceleration). The units are meters per second divided by seconds (m/s)/s, which is meters per second squared (m/s^2).
The car accelerates from 15 to 30 m/s, so it changes its speed by (30–15)=15 m/s, over an interval of 2 seconds. The acceleration therefore equals A = 15/2 = 7.5 m/s^2. Done.
Kinematic problems like this get harder when the calculations involve distance.
