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

[math]\displaystyle{ F_g=G\frac{m_1 m_2}{r^2}, }[/math]

File:NewtonsLawOfUniversalGravitation.svg

In this equation:

• [math]\displaystyle{ F_g }[/math] is the total gravitational force between the two objects.
• [math]\displaystyle{ G }[/math] is the gravitational constant.
• [math]\displaystyle{ m_1 }[/math] is the mass of the first object.
• [math]\displaystyle{ m_2 }[/math] is the mass of the second object.
• [math]\displaystyle{ r }[/math] is the distance between the centers of the objects.

In SI units, [math]\displaystyle{ F_g }[/math] is measured in newtons (N), [math]\displaystyle{ m_1 }[/math] and [math]\displaystyle{ m_2 }[/math] in kilograms (kg), [math]\displaystyle{ r }[/math] in meters (m), and the constant [math]\displaystyle{ G }[/math] is approximately equal to 6.674×10⁻¹¹ N m² kg⁻².

Newton's Law Of Universal Gravitation Media

• Gravity Big G Measurements NIST.png

  Error plot showing experimental values for G

• Earth-G-force.png

  Gravitational field strength within the Earth

• Gravity field near earth.gif

  Gravity field near the surface of the Earth – an object is shown accelerating toward the surface

• Gravitymacroscopic.svg

  Gravity field surrounding Earth from a macroscopic perspective.