Gravitational field strengthAQA A-Level Physics: Mind map

Exam questions on Gravitational field strength

1. A Mars lander team models Mars as a uniform sphere of mass 6.42 × 10²³ kg and radius 3.39 × 10⁶ m. A small test mass is released at the surface of the planet.
   Calculate the gravitational field strength at the surface of Mars. Use $G = 6.67 \times 10^{-11}\ \mathrm{N\,m^2\,kg^{-2}}$.2 marks
2. The gravitational field around an isolated, uniform planet is represented by gravitational field lines drawn in the space outside the planet.
   Explain why the gravitational field near the surface of the planet can be treated as uniform over a height of a few metres, but not over a height of several thousand kilometres.2 marks
3. The International Space Station orbits the Earth at a height of 400 km above the surface. The Earth may be treated as a uniform sphere of mass 5.97 × 10²⁴ kg and radius 6.37 × 10⁶ m.
   Calculate the gravitational field strength at the height of the space station. Use $G = 6.67 \times 10^{-11}\ \mathrm{N\,m^2\,kg^{-2}}$.3 marks