Newton's law of universal gravitation

Newton's universal law of gravitation is a physical law that describes the attraction between two objects with mass. Sir Isaac Newton talked about it in his book Philosophiae Naturalis Principia Mathematica. The law is part of classical mechanics.

The formula is

$F_{g}=G{\frac {m_{1}m_{2}}{r^{2}}},$

In this equation:

• $F_{g}$ is the total gravitational force between the two objects.
• $G$ is the gravitational constant.
• $m_{1}$ is the mass of the first object.
• $m_{2}$ is the mass of the second object.
• $r$ is the distance between the centers of the objects.

In SI units, $F_{g}$ is measured in newtons (N), $m_{1}$ and $m_{2}$ in kilograms (kg), $r$ in meters (m), and the constant $G$ is approximately equal to 6.674×10⁻¹¹ N m² kg⁻².