= Gravitational acceleration
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= Newtonian gravity
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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.
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