The gravitational field intensity at a point in a gravitational field can be defined as the gravitational force acting on a unit mass at that point. It is the measure of the strength of the gravitational field.

The gravitational Field strength is equal to the acceleration due to gravity
g = force/mass
The relationship between Gravitational constant, G and acceleration due to gravity, g is given as thus:

Example 1: The earth's gravitational field intensity at its surface is about (G = 6.7 × 10⁻¹¹Nm²/kg², mass of the earth is 6 × 10²⁴kg, radius of the earth is 6.4 × 10⁶m, g on the earth = 9.8m/s²)(JAMB)

F = mg
but g = acceleration due to gravity = gravitational field intensity
:. g = 9.8N/kg

Example 2: The force experienced by an object of mass 60.0kg in the moon's gravitational field is 1.002 x 10²N. What is the intensity of the gravitational field?(JAMB)

g = force / mass
force = 1.002 × 10²N
mass = 60kg
g = 1.002 × 10² / 60
g = 1.67N/kg

Example 3: What is the acceleration due to gravity on the Moon, if g is 10m/s² on the Earth? (JAMB)

gravity of earth = 10m/s²
But gravity of moon = ⅙ that of earth
gravity of moon = 10 × ⅙
= 1.67m/s²

Example 4: The earth is four times the size of the moon and the acceleration due to gravity on the earth is 80 times that on the moon. The ratio of the mass of the moon to that of the earth is