Final answer:
The skateboarder will take 4.5 seconds to stop if decelerating at a rate of -2 m/s.
Step-by-step explanation:
To find the time it takes for the skateboarder to stop, we can use the formula:
final velocity = initial velocity + (acceleration x time)
Since the skateboarder is decelerating at a rate of -2 m/s, the acceleration is -2 m/s².
Plugging in the values, we have:
0 = 9 + (-2 * time)
Simplifying the equation, we get:
time = 4.5 seconds
Therefore, the answer is Option a. 4.5 seconds.