* Velocity is a vector: It has both magnitude (speed) and direction.
* Changing velocity means either:
* Change in speed: The object is speeding up or slowing down.
* Change in direction: The object is turning or curving its path.
* Both: The object is speeding up/slowing down *and* changing direction.
On a motion diagram:
* Constant velocity: The arrows representing the object's velocity are all the same length and point in the same direction.
* Changing velocity: The arrows either:
* Increase or decrease in length: Showing a change in speed.
* Change direction: Showing a change in direction.
* Both increase/decrease in length AND change direction: Showing a change in both speed and direction.
Example:
Imagine a car moving in a straight line, then turning left. On a motion diagram:
* The arrows representing the car's motion would be the same length while it travels straight, showing constant speed.
* When the car turns, the arrows would change direction to show the car's change in direction.
In essence, a motion diagram with changing velocity arrows is telling you the object is accelerating.
