Which phenomenon did Galileo's work help to establish regarding falling bodies?

Galileo's work with falling bodies was foundational in establishing the concept of uniform acceleration. Through his experiments, he demonstrated that objects in free fall, regardless of their mass, experience the same constant acceleration due to gravity, in the absence of air resistance. He showed that, in a vacuum, a feather and a hammer dropped simultaneously would hit the ground at the same time, highlighting that the acceleration due to gravity is consistent for all objects.

This principle of uniform acceleration implies that the rate at which the velocity of an object changes while falling is constant. Galileo's observations laid the groundwork for Newton's later work, which further defined the laws of motion and gravitation. While other aspects such as air resistance and the influence of mass on acceleration were subjects that would be discussed later by other scientists, Galileo's critical contribution was his clear illustration of how falling bodies accelerate uniformly under the influence of gravity alone, setting the stage for future advancements in physics.