In our Solar System, the planets Mars and Neptune have approximately circular orbits around the Sun. The mean orbital radius of Mars is 1.5 AU1.5\text{ AU}1.5 AU and the mean orbital radius of Neptune is 30.0 AU30.0\text{ AU}30.0 AU.
What is the ratio of the orbital speed of Mars to the orbital speed of Neptune, vMarsvNeptune\displaystyle \frac{v_{\text{Mars}}}{v_{\text{Neptune}}}vNeptunevMars?
202020
4.54.54.5
0.220.220.22
0.0500.0500.050
28 exam-style questions on Edexcel GCSE Physics 7.1 The Solar System and gravity, covering 7.1.1 Weight and g on different bodies in space, 7.1.2 The Solar System, 7.1.3 Changing ideas about the Solar System, 7.1.4 Orbits of moons, planets, comets and satellites, and 7.1.5 Gravity and orbital motion. Each one has a worked solution and a mark scheme showing where the marks go.