(a)[3]
Fig. 8.1 displays these planets aligned with the Sun. They move around the Sun in the direction shown. On Fig. 8.1, mark and label the positions of the three planets 110 days after the position shown in Fig. 8.1.
(b(i))[1]
All three planets have approximately the same average density. Suggest why the gravitational field strength at the surface of Mercury is much smaller than at the surface of Venus.
(b(ii))[2]
An object weighs $37\,\text{N}$ at Mercury's surface. Calculate its weight at the Earth's surface. Show your working.
(c)[1]
State what is meant by a ‘moon’.
(d)[3]
The Sun will eventually use up all of its hydrogen. Describe what happens to the Sun when the hydrogen runs out.