An asteroid of mass 4.0×1015kg is approximately spherical and may be treated as a point mass for points outside its surface.
(i) Calculate the magnitude of the gravitational field intensity at a point 200m from its centre.
(ii) Determine the field intensity at a point 400m from the centre.
(iii) Find the ratio of the answers obtained in parts (i) and (ii) and comment on the result.