(a)[1]
Define gravitational field in terms of force per unit mass.
(b(i))[2]
On Fig. 1.1, draw gravitational field lines outside the planet so as to show the gravitational field produced by the planet.
(b(ii))[2]
A satellite moves in a circular orbit around the planet. Explain, with reference to your answer in (b)(i), why the satellite follows a circular path.
(b)
A spherical planet may be treated as though all of its mass were concentrated at the centre.
(c)
An object is at rest on the Earth’s surface at the Equator. The Earth’s radius is $6.4 \times 10^6\,\text{m}$.
(c(i))[3]
Determine the centripetal acceleration for the object.
(c(ii))[2]
Describe how the two forces acting on the object produce this centripetal acceleration. You may include a diagram if you want.