**Gravitational Field**

The space around an object within which its force of gravitation is experienced is termed as gravitational field.

**What is Gravitational field Intensity?**

The gravitational field intensity is the intensity of the gravitational field of a material body at any point in its field is defined as the force experienced by a unit mass placed at that point, provided the unit mass itself does not produce any change in the field of the body.

Assume,

M = Mass of an object around which a gravitational field occurs.

m = A test mass located in this field.

The test mass is so selected that it does not influence the gravitational field. The arrow over \(\overrightarrow{E}\) specifies it is a vector quantity, although mass is a scalar unit.

A force \(\overrightarrow{F}\) field is the force felt by the unit mass m. The strength \(\overrightarrow{E}\) of the field is the force felt by the unit mass.

\(\overrightarrow{E}\,=\,\frac{\overrightarrow{F}}{m}\), \(\overrightarrow{E}\) is a vector quantity. It is directed towards M.

\(\overrightarrow{E}\,=\,\frac{\overrightarrow{F}}{m}\,=\,\frac{m\,\times \,\overrightarrow{a}}{m}\,=\,\overrightarrow{a}\).

If the test mass m was free to move, it world move with acceleration towards M. So, \(\overrightarrow{a}\) = Free acceleration.

The intensity is described as the free acceleration experienced by a trial mass at that point.

**Units of Gravitational Field: **If M is the mass of Earth then \(\overrightarrow{E}\,=\,\frac{m\overrightarrow{g}}{m}\,=\,\overrightarrow{g}\).

Where,

\(\overrightarrow{g}\) = Acceleration due to gravity.

The SI system of Gravitational Field is N/ kg (or) m/sec².