Here's why:
* Change in speed: This is the most intuitive definition of acceleration. If you're speeding up or slowing down, you're accelerating.
* Change in direction: Even if you're maintaining a constant speed, if you're changing direction (like driving around a corner), you're still accelerating. This is because acceleration is a vector quantity, meaning it has both magnitude (speed) and direction.
In essence, acceleration is any change in an object's velocity.
