What is the definition of acceleration?

Acceleration is defined as the rate at which an object changes its velocity, which encompasses both speeding up and slowing down. It's crucial to understand that acceleration is not just about increasing speed; it also addresses the change in motion when an object decreases its speed. In physics, when we talk about acceleration, we're referring to how quickly this change in velocity occurs over a specific period of time, which can include increasing momentum or deceleration.

The other concepts mentioned, such as how quickly something is moving or the total distance covered, do not encapsulate the complete nature of acceleration. While they relate to aspects of motion, they do not precisely define the dynamic nature of changes in speed, which is central to the concept of acceleration. Thus, the chosen definition accurately captures the essence of acceleration in the context of motion and physics.