Final answer:
The acceleration of a racing car whose speed decreases uniformly from 66 m/s to 44 m/s over an 11s period is -2 m/s².
Step-by-step explanation:
The subject of the question is the calculation of acceleration when a racing car decreases its speed over a period of time. To find the acceleration, we use the formula: acceleration = (final velocity - initial velocity) / time. In this case, the initial velocity is 66 m/s, the final velocity is 44 m/s, and the time is 11 seconds.
Plugging in the values gives us: acceleration = (44 m/s - 66 m/s) / 11 s = -22 m/s / 11 s = -2 m/s², which means the correct answer is B. -2 m/s². This negative sign indicates that the car is slowing down, or in other words, the speed is decreased.