Final answer:
The car's deceleration is -5 m/s², which means its speed is decreasing by 5 m/s each second. Deceleration is considered a negative acceleration.
Step-by-step explanation:
The student's question relates to the concept of deceleration, which is a type of acceleration where an object is slowing down. In physics terms, acceleration is defined as the rate at which the velocity of an object changes over time. Deceleration is simply negative acceleration, meaning the velocity is decreasing.
If a car is slowing down by 5 m/s every second, then its deceleration is -5 m/s². This is because 'deceleration' refers to the rate of decrease in velocity, which in this case is 5 m/s every second; so, the acceleration is negative, indicating a reduction in speed.
Answer:
The car's deceleration is -5 m/s², which corresponds to option b).