Here's why:

* Acceleration due to gravity (g) is the acceleration experienced by an object due to the gravitational force of the Earth. It's a specific value (approximately 9.8 m/s²) near the Earth's surface.

* Gravitational field strength (g) is a more general concept that describes the gravitational force experienced by a unit mass at a specific point in space. It's a vector quantity, meaning it has both magnitude and direction.

Relationship:

The acceleration due to gravity (g) is the magnitude of the gravitational field strength (g) at a particular location.

Example:

The gravitational field strength at the surface of the Earth is 9.8 N/kg. This means that a 1 kg object experiences a force of 9.8 N due to gravity. The acceleration due to gravity is also 9.8 m/s².

In summary:

While "acceleration due to gravity" focuses on the acceleration of an object, "gravitational field strength" describes the force per unit mass at a location. They are equivalent in the sense that the magnitude of the gravitational field strength at a specific point is equal to the acceleration due to gravity at that point.