 Gravitational acceleration

Gravitational acceleration is the acceleration of a test particle in free fall in a Newtonian gravitational field. It is a vector pointing along that field; $g$ commonly denotes its positive magnitude. Near Earth's surface, the magnitude is approximately constant over shallow vertical scales. For a fixed spherical source it instead varies as $g(r)=\mu /r^2$, where $\mu$ is the standard gravitational parameter.

This is distinct from gravitational weight, the force $m\mathbf{g}$, and from apparent weight, the support force a scale measures. An orbiting body can have substantial gravitational acceleration while its apparent weight is zero.

Gravitational acceleration is the acceleration experienced by an object due to the gravitational force exerted by a massive body, such as a planet or a star. It is commonly denoted by the symbol \( g \). On the surface of the Earth, the average value of gravitational acceleration is approximately \( 9.81 \, \text{m/s}^2 \).