A relay spacecraft moves in stable circular orbits around Uranus. The orbital radius is measured from the centre of Uranus.
| Orbit | Orbital radius | Orbital speed |
|---|---|---|
| A | 4.0 × 107 m | 12.0 km/s |
| B | 9.0 × 107 m | 8.0 km/s |
Explain how the measurements support the relationship between orbital radius and speed for a stable circular orbit.
A student concludes that the spacecraft is not accelerating in orbit B because its speed remains at 8.0 km/s.
Explain whether the student's conclusion is correct.
Engineers consider two proposed new stable circular orbits.
| Proposed orbit | Orbital speed |
|---|---|
| X | 10.0 km/s |
| Y | 6.0 km/s |
The new orbit must have a radius between the radii of orbit A and orbit B.
State which proposed orbit meets this requirement. Explain your answer.
80 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.