Newtons Law Of Gravitation

Key Idea: Where gravitational field due to earth and moon cancel each other, there the gravitational force is equal.
From Newtons law of gravitational the force of attraction between any two material particles is given by

where are masses and is the distance between the two.
Since gravitational fields cancel each other the force of attraction is same and opposite. i.e.,



Taking square root of the above expression, we have



Hence, distance of that point from moon is 6R.