How strong is gravity on Earth?
Gravity of Earth
The precise strength of Earth's gravity varies depending on location. The nominal "average" value at Earth's surface, known as standard gravity is, by definition, 9.80665m/s2.[4] This quantity is denoted variously as gn, ge (though this sometimes means the normal equatorial value on Earth, 9.78033m/s2), g0, gee, or simply g (which is also used for the variable local value).
Reaction (physics)
Any mass on earth is pulled down by the gravitational force of the earth; this force is also called its weight. The corresponding 'reaction' is the gravitational force that mass exerts on the planet.