The gravitational field E at a position called P at ( x , y ) = ( − − p , 0 ) on the x -axis due to a point of mass M at the origin is E point = G M p 2 Suppose that this mass is moved upwards along the y -axis to the point ( − − p , R ) . The distance between P and the point mass is now longer than before; It becomes the hypotenuse of the right triangle with legs p and R which is p 2 + R 2 . Hence, the gravitational field of the elevated point is: E elevated point = G M p 2 + R 2