# Newton's law of universal gravitation

Statue of Isaac Newton in the chapel of Trinity College, Cambridge

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:

• Fg is the total gravitational force between the two objects.
• G is the gravitational constant.
• m1 is the mass of the first object.
• m2 is the mass of the second object.
• r is the distance between the centres of the objects.

In SI units, Fg is measured in newtons (N), m1 and m2 in kilograms (kg), r in metres (m), and the constant 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 2009124. Check date values in: |access-date= (help)
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. doi:10.1103/RevModPhys.88.035009.