Understanding the Concepts

* Velocity: The rate at which an object changes its position. It has both magnitude (speed) and direction.

* Acceleration: The rate at which an object changes its velocity. It's also a vector quantity.

* Average Acceleration: The change in velocity divided by the time interval over which the change occurs.

Formula

Average Acceleration (a) = (Final Velocity (v_f) - Initial Velocity (v_i)) / Time (t)

Given Information

* Initial Velocity (v_i) = +9.5 m/s

* Final Velocity (v_f) = 0 m/s

* Time (t) = 3 seconds

Calculation

1. Plug the values into the formula:

a = (0 m/s - 9.5 m/s) / 3 s

2. Calculate:

a = -9.5 m/s / 3 s

a = -3.17 m/s²

Answer

The average acceleration of the car during this time interval is -3.17 m/s². The negative sign indicates that the acceleration is in the opposite direction to the initial velocity, meaning the car is decelerating or slowing down.