Relation between universal constant (G) and gravitational acceleration (g)

Suppose if,  

M = Mass of earth

m = mass of falling object

R = Radius of earth 

Then, gravitational acceleration force,

By the second law of newton's velocity law,

Now on comparison of eqⁿ (1) and (2), we say that eqⁿ (1) =  eqⁿ (2)

We know that the formula of density is,

On putting the value of 'M' in eqⁿ (3)

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