1. Change in Speed:

* Acceleration: This is the most common reason for a change in velocity. Acceleration means an object is speeding up or slowing down.

* Example: A car accelerating from a stop sign or braking before a red light.

* Constant Velocity: Objects moving at a constant speed in a straight line have no acceleration and therefore no change in velocity.

2. Change in Direction:

* Even if the speed is constant, any change in direction results in a change in velocity. Velocity is a vector quantity, meaning it has both magnitude (speed) and direction.

* Example: A car driving around a curve at a constant speed still has changing velocity because its direction is changing.

Here's a breakdown of how velocity is affected by each:

* Increased Speed: Velocity increases in the same direction as the motion.

* Decreased Speed: Velocity decreases in the same direction as the motion.

* Change in Direction: The velocity vector changes, even if the speed remains the same. This is because velocity is a vector quantity that includes both speed and direction.

Key Takeaway:

* Velocity is a vector quantity that describes both the speed and direction of an object's motion.

* Any change in speed or direction results in a change in velocity.