If velocity is constant, then acceleration is what?

When velocity remains constant, it indicates that an object is maintaining a steady speed in a designated direction without any changes. In biomechanics, acceleration is defined as the rate at which an object's velocity changes over time. If there is no change in velocity—meaning the speed and direction remain unchanged—then the acceleration must be zero.

This situation can occur in a variety of mechanical systems, including those studied in biomechanics, where steady movement is essential, such as a runner maintaining a constant speed on a track. Understanding that acceleration equals the change in velocity over time aids in grasping why, when velocity does not change, acceleration must indeed be zero. This is a fundamental concept in both physics and biomechanics that helps in analyzing motion effectively.