Question

write the formula to find the magnitude of the gravitional force'F' between the earth of mass 'M' and radius 'R' and an object of mass 'm' on the surface of the earth

Answer 1

F=(G×M×m)÷(R^2)
you can find this in any book of mechanics

Answer 2

$f = \frac{gm1m2}{ {r}^{2} }$
Where m1 is the mass if earth and m2 is the mass of object
And r is the distance on object to the center of earth