To calculate the value of g, we should put

the values of G, M and R ,

namely, universal gravitational constant, G = 6.7 × 10^{–11} N m^{2 }kg^{-2}

, mass of the earth, M = 6 × 10^{24} kg, and radius of the earth, R = 6.4 × 10^{6} m.

g =GM/R^{2}

g = (6.7 × 10^{–11} ) X (6 × 10^{24} ) / ( 6.4 × 10^{6})^{2}

g = 9.8 m s^{–2}

.

Thus, the value of acceleration due to gravity of the earth, **g = 9.8 m s ^{–2}**

.