* Gravity: A fundamental force of nature that attracts objects with mass towards each other. The more massive an object, the stronger its gravitational pull.

* Earth's Gravity: The Earth has a large mass, creating a strong gravitational field that pulls objects towards its center.

* Free Fall: When an object is only under the influence of gravity, it experiences free fall. This means there are no other forces acting on it, like air resistance.

Important Points:

* Air Resistance: In reality, air resistance (also known as drag) acts on objects falling through the air. This force opposes the object's motion and slows it down.

* Terminal Velocity: As an object falls, air resistance increases until it balances the force of gravity. At this point, the object stops accelerating and falls at a constant speed called terminal velocity.

* Weightlessness: Astronauts in orbit around Earth experience weightlessness because they are constantly in free fall, falling around the Earth at a high speed.

In summary: Free fall is the motion of an object solely under the influence of gravity. It's a fundamental concept in physics that helps us understand the motion of objects in the universe.