Blast into 2026: Conquer the Astronomy Challenge – Your Cosmic Adventure Awaits!

In the absence of air resistance, all objects fall at the same rate due to the uniform acceleration produced by gravity. This principle stems from Galileo's experiments, which demonstrated that the acceleration due to gravity is constant at approximately 9.81 m/s² near the Earth's surface, regardless of the mass of the object.

This means that whether an object is heavy or light, it will experience the same gravitational force per unit mass, resulting in identical acceleration. For instance, if you were to drop a marble and a hammer in a vacuum (where air resistance is eliminated), both would hit the ground simultaneously. This uniform behavior occurs because gravity affects all objects equally, allowing for a clear demonstration of the effects of gravitational acceleration alone.

Other choices suggest that either mass, shape, or absence of gravity influences falling rates, but in a vacuum, these factors become irrelevant since the only influence is the constant pull of gravity.