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What is 'g' in physics?

Whenever an object falls towards the earth, an acceleration is involved. This acceleration is due to the earth's gravitational force. Hence it is called acceleration due to gravity. It is denoted by 'g'.

Acceleration due to gravity, g = GM_c

where M_c = Mass of earth

R = Radius of earth.

Thus 'g' does not depend uopon the mass of the falling object, i.e., the acceleration due to gravity is same for the freely falling bodies.

We know, g = GM_c

The SI unit of, G is Nm²/kg² (= m³kg^-1s^-2)

M_c in kg and R in m.

Therefore,

Unit of g = m³kg^-1s^-2 x kg

                 = m/s²

So, the S.I Unit of g is m/s² or m/s^-2.