Citation:
$a = \frac{F}{m} = G \frac{M}{r^2}$ is a fundamental equation that relates the acceleration of an object to the forces acting upon it, specifically the force of gravity. This equation is central to both Newton's Law of Universal Gravitation and Einstein's Theory of General Relativity, as it describes the relationship between an object's mass, the gravitational force acting on it, and its resulting acceleration.