(a) Calculate in geometrized units: (i) The Newtonian potential of the Sun at the Sun's surface,...

(a) Calculate in geometrized units:
(i) The Newtonian potential φ of the Sun at the Sun's surface, radius 6.960 × 108m;
(ii) The Newtonian potential φ of the Sun at the radius of Earth's orbit, r = 1AU = 1.496 × 1011m;
(iii) The Newtonian potential φ of Earth at its surface, radius = 6.371 × 106m;
(iv) The velocity of Earth in its orbit around the Sun.
(b) You should have found that your answer to (ii) was larger than to (iii). Why, then, do we on Earth feel Earth's gravitational pull much more than the Sun's?
(c) Show that a circular orbit around a body of mass M has an orbital velocity, in Newtonian theory, of v2 = −φ, where φ is the Newtonian potential.