1. Speed: Acceleration occurs when an object's speed increases or decreases.
2. Direction: Acceleration also occurs when an object changes its direction of motion, even if its speed remains constant.
Think of it this way:
* Speeding up means you're accelerating.
* Slowing down means you're also accelerating (in the opposite direction of your motion).
* Turning a corner means you're accelerating because your direction is changing, even if your speed remains constant.
