Here's a breakdown:

* Acceleration: It refers to the change in velocity over time. A positive acceleration means the object is speeding up, while negative acceleration means it's slowing down.

* Due to gravity: The change in velocity is caused by the force of gravity pulling the object towards the Earth's center.

* Free fall: This means the object is falling without any other forces acting on it, like air resistance.

Key Points:

* Constant value: Near the Earth's surface, acceleration due to gravity is approximately 9.8 m/s², meaning an object's velocity increases by 9.8 meters per second every second it falls.

* Direction: The acceleration due to gravity is always directed towards the center of the Earth.

* Independent of mass: The acceleration due to gravity is the same for all objects, regardless of their mass (neglecting air resistance). This means a feather and a bowling ball will fall at the same rate in a vacuum.

Symbol: The symbol for acceleration due to gravity is g.

Understanding:

Imagine dropping a ball. As it falls, it gets faster and faster. This increase in speed is the acceleration caused by gravity. The higher the gravitational force, the faster the object will accelerate.

Note: The acceleration due to gravity is not a constant value everywhere on Earth. It varies slightly depending on factors like altitude and latitude.