* Change in speed:
* Increasing speed: A car accelerating from a stoplight or a ball rolling down a hill.
* Decreasing speed: A car braking to a stop or a ball thrown upwards slowing down as it reaches its peak.
* Change in direction:
* Turning: A car turning a corner, a planet orbiting a star, or a ball swinging on a string.
* Curving: A ball thrown in an arc or a roller coaster going around a loop.
In summary, acceleration occurs whenever:
* The object speeds up.
* The object slows down.
* The object changes direction.
Important Note: Even if an object is moving at a constant speed, if it changes direction, it is still accelerating.
