Astronomers observe two planets, J and K, moving in circular orbits around the same star. The table shows the speed and direction of motion of each planet at two observations.
| Planet | First observation: speed in km/s | First observation: direction of motion | Second observation: speed in km/s | Second observation: direction of motion |
|---|---|---|---|---|
| J | 35 | east | 35 | north |
| K | 24 | south | 24 | south-east |
A student says, “Neither planet is accelerating, because the speed of each planet does not change.”
Evaluate the student's claim. Use data from the table.
Explain how the star's gravitational force on planet J produces the motion shown in the table.
State what would happen to the path of planet J if the star's gravitational attraction on it suddenly became zero.
84 exam-style questions on AQA GCSE Physics 8.1 Solar system; stability of orbital motions; satellites, covering 8.1.1 Our solar system, 8.1.2 The life cycle of a star, and 8.1.3 Orbital motion, natural and artificial satellites. Each one has a worked solution and a mark scheme showing where the marks go.