Gravitational potential and comparison with electric fieldsEdexcel A-Level Physics: Mind map

Exam questions on Gravitational potential and comparison with electric fields

1. An engineer is planning to launch a probe of mass 450 kg from the surface of the Earth. The Earth may be treated as a uniform sphere of mass 5.97×10²⁴ kg and radius 6.37×10⁶ m, and the gravitational constant is G = 6.67×10⁻¹¹ N m² kg⁻².
   The probe is raised from the surface of the Earth to a height equal to the radius of the Earth. Calculate the increase in the gravitational potential energy of the probe.2 marks
2. In a simple model of a hydrogen atom, an electron of mass 9.11×10⁻³¹ kg and charge −1.60×10⁻¹⁹ C is a distance of 5.3×10⁻¹¹ m from a proton of mass 1.67×10⁻²⁷ kg and charge +1.60×10⁻¹⁹ C. Both particles are treated as point masses and point charges. Take G = 6.67×10⁻¹¹ N m² kg⁻² and ε₀ = 8.85×10⁻¹² F m⁻¹.
   Calculate the gravitational force between the proton and the electron.2 marks
3. A lunar lander of mass 1200 kg is on the surface of the Moon. The Moon may be treated as a uniform sphere of mass 7.35×10²² kg and radius 1.74×10⁶ m. Take G = 6.67×10⁻¹¹ N m² kg⁻². The surface field strength of the Moon is 1.62 N kg⁻¹.
   Calculate the gravitational potential at the surface of the Moon and explain why the value is negative.3 marks