Gravitational field strength (g): A measure of how strong gravity is at a particular location near Earth's surface. It determines how quickly objects accelerate towards Earth when in free fall.
Mass (m): The amount of matter an object contains. It is a measure of the object's inertia and determines how much force is required to accelerate it.
Reference point: A chosen location or position from which heights or distances are measured. In the context of gravitational potential energy, it is often the ground level or a specific reference height.