Here's why:
* Acceleration is a change in velocity.
* Velocity is a vector quantity, meaning it has both magnitude (speed) and direction.
* Therefore, even if the object's speed remains constant, a change in direction means its velocity has changed, which constitutes acceleration.
Examples:
* A car driving around a circular track at a constant speed is accelerating because its direction is constantly changing.
* A ball thrown horizontally in the air experiences acceleration due to gravity, causing it to change direction downwards.
