A spherical planet of radius R R\,R has a uniform density ρ\rhoρ. A satellite orbits the planet in a circular path of radius approximately equal to R R\,R with an orbital speed vvv.
What is the mean density ρ \rho\,ρ of the planet?
3v24πGR2\frac{3v^2}{4\pi G R^2}4πGR23v2
3v4πGR\frac{3v}{4\pi G R}4πGR3v
4πGR23v2\frac{4\pi G R^2}{3v^2}3v24πGR2
3v2R24πG\frac{3v^2 R^2}{4\pi G}4πG3v2R2
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.