A solid sphere of radius R has uniform density ρ.
(a) Derive an expression for the gravitational field intensity at a point situated at a distance r(≥R) from the centre of the sphere.
(b) Show that for a point inside the sphere (r≤R) the field intensity varies directly with r and attains its maximum value at the surface.
(c) Draw and label a qualitative graph of gravitational field intensity g versus distance r from the centre for the range 0≤r≤2R.