* Acceleration is a vector: It has both magnitude (how much) and direction.
* Slowing down means acceleration is in the opposite direction of velocity: If an object is moving to the right, slowing down means its acceleration is pointing to the left.
* Increasing magnitude doesn't mean the direction changes: Acceleration can increase in magnitude while still pointing in the opposite direction of the object's velocity.
Example:
Imagine a car driving to the right and slamming on the brakes.
* The car is slowing down: Its velocity is decreasing.
* The acceleration is increasing: As the brakes are applied harder, the car's acceleration to the left increases in magnitude.
In this case, the car is slowing down (velocity decreasing) while its acceleration to the left is increasing in magnitude.
