Definition:Gravity
Definition
Gravity is the tendency for a body to move downwards, as a result of its weight.
It is a local manifestation of the phenomenon of gravitation, whether on Earth or some other celestial body
Force of Gravity on Earth
When used in an unqualified sense, it is usual for the term force of gravity to mean the downward force on a body at the surface of Earth.
From Gravity at Earth's Surface, this is approximately $9.8 \ \mathrm N \ \mathrm{kg}^{-1}$
The force of gravity varies across the Earth's surface, and therefore it makes little sense to use it as a standard.
However, the CGPM adopted a standard value of Acceleration Due to Gravity at Earth's Surface of $9.806 \, 65 \, \mathrm N \, \mathrm{kg}^{-1}$ in $1901$.
Also known as
Gravity is also known as gravitation.
However, as it is often referred to in common usage as the force of gravity, in particular at the surface of Earth, it is recommended that the terms are kept separate.
Also see
- Results about gravity can be found here.
Sources
- 1966: Isaac Asimov: Understanding Physics ... (previous) ... (next): $\text {I}$: Motion, Sound and Heat: Chapter $2$: Falling Bodies: Free Fall
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): gravity
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): gravity
- 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): gravity