(a(i))[2]
State what gravitational potential at a point means.
(a(ii))[2]
Suggest why gravitational potential is approximately constant when the change in height near the Earth’s surface is small.
(b)[3]
The Moon may be treated as a uniform sphere with a diameter of $3.5 \times 10^3\,\text{km}$ and a mass of $7.4 \times 10^{22}\,\text{kg}$. A meteor hits the Moon and, during the collision, a rock is launched from the Moon’s surface with an initial speed $v$. Assuming that the Moon is isolated in space, determine the minimum speed of the rock so that it does not return to the Moon’s surface. Explain your working. Give your answer in $\text{m s}^{-1}$.