Final answer:
The average acceleration of the automobile, which is slowing down, is calculated using the formula a = (Vf - Vi) / t. Substituting the given values results in an acceleration of -2.0 m/s², indicating deceleration. The correct answer is 2.0 m/s².
Step-by-step explanation:
Calculating Average Acceleration
The question involves a scenario where an automobile slows down, which means we are dealing with deceleration. Deceleration is simply a negative acceleration. To find the average acceleration, we use the formula:
a = (Vf - Vi) / t
Where 'a' is the average acceleration, 'Vf' is the final velocity, 'Vi' is the initial velocity, and 't' is the time over which the change in velocity occurs.
In this case, Vf = 18 m/s (final velocity), Vi = 26 m/s (initial velocity), and t = 4.0 s (time). Let's substitute these values:
a = (18 m/s - 26 m/s) / 4.0 s
a = (-8 m/s) / 4.0 s
a = -2.0 m/s²
The acceleration is -2.0 m/s², where the negative sign indicates deceleration. Option d. 2.0 m/s² is the correct magnitude of the acceleration.