Here's a breakdown:

* Acceleration: A measure of how quickly the velocity of an object changes.

* Positive Acceleration: Indicates that the velocity is increasing in the direction of motion.

* Negative Acceleration: Indicates that the velocity is decreasing in the direction of motion (or increasing in the opposite direction).

Example:

Imagine a car moving forward (positive direction).

* If the car speeds up, its velocity is increasing in the direction of motion, and its acceleration is positive.

* If the car slows down, its velocity is decreasing in the direction of motion, and its acceleration is negative (even though the car is still moving forward).

Important Note: Acceleration is a vector quantity, meaning it has both magnitude and direction. So, when we say positive acceleration, we're talking about the direction of acceleration relative to the direction of motion.