(a(i))[2]
State the meaning of gravitational potential at a point.
(a(ii))[2]
Suggest why gravitational potential is approximately constant for a small change in height near the Earth’s surface.
(b)[3]
The Moon can be modelled 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 collides with the Moon and, during the impact, a rock is launched from the Moon’s surface with initial speed $v$. Assuming the Moon is isolated in space, determine the minimum speed of the rock so that it does not fall back to the Moon’s surface. Explain your working.