According to Galileo, what is a principle of free-falling objects?

Galileo's principle regarding free-falling objects emphasizes that these objects experience uniform acceleration due to gravity. This means that as an object falls, its velocity increases at a constant rate, specifically at approximately 9.81 meters per second squared near the Earth's surface. This concept marked a significant advancement in understanding motion, shifting away from the pre-Galilean belief that heavier objects fell faster than lighter ones.

The uniform acceleration applies regardless of the object's mass, provided that air resistance is negligible. This principle laid the groundwork for Newtonian physics and allows for predictable calculations of how far and how fast an object will fall over time. Galileo's observations and experiments demonstrated that, in a vacuum where air resistance is absent, all objects fall at the same rate, affirming this uniform acceleration characteristic.

The other concepts, such as increasing resistance, constant variation in speed, or always returning to the original position, do not align with the fundamental principles Galileo proposed regarding the motion of free-falling objects.