# Newton's law of universal gravitation

classical mechanics physical law

Newton's universal law of gravitation is a physical law that describes the attraction between two objects with mass. It is talked about in Isaac Newton's Philosophiae Naturalis Principia Mathematica.[1][2] The law is part of classical mechanics.

The formula is

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

In this equation:

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

In SI units, ${\displaystyle F_{g}}$ is measured in newtons (N), ${\displaystyle m_{1}}$ and ${\displaystyle m_{2}}$ in kilograms (kg), ${\displaystyle r}$ in meters (m), and the constant ${\displaystyle G}$ is approximately equal to 6.674×10−11 N m2 kg−2.[3]

## References

1. "Sir Isaac Newton: The Universal Law of Gravitation". Astronomy 161. Retrieved 2009-01-24.
2. Cox, Brian; Forshaw, Jeff (2011). The Quantum Universe: Everything That Can Happen Does Happen. Allen Lane. p. 14. ISBN 978-1-846-14432-5.
3. Mohr, Peter J.; Newell, David B.; Taylor, Barry N. (July–September 2016). "CODATA recommended values of the fundamental physical constants: 2014". Reviews of Modern Physics. 88 (3): 035009. arXiv:1507.07956. Bibcode:2016RvMP...88c5009M. doi:10.1103/RevModPhys.88.035009. S2CID 1115862.