A planet of radius R R\,R has an acceleration due to gravity at its surface of ggg. A spacecraft of mass m m\,m is in a stable circular orbit around the planet at an altitude where the local gravitational field strength is g9\displaystyle \frac{g}{9}9g.
What is the orbital speed of the spacecraft?
13gR\frac{1}{3}\sqrt{gR}31gR
12gR\frac{1}{2}\sqrt{gR}21gR
gR3\sqrt{\frac{gR}{3}}3gR
2gR3\sqrt{\frac{2gR}{3}}32gR
52 exam-style questions on AQA A Level Physics Gravitational fields (A-level only), covering Newton's law (A-level only), Gravitational field strength (A-level only), Gravitational potential (A-level only), and Orbits of planets and satellites (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.