Physics Topic: Gravitational Fields

  1. recall and use Newton’s law of gravitation in the form F = Gm1m2/r2

  2. derive, from Newton’s law of gravitation and the definition of gravitational field strength, the field strength due to a point mass, g = Gm/r2

  3. recall and use g = Gm/r2 for the gravitational field strength due to a point mass to solve problems

  4. show an understanding that near the surface of the Earth, gravitational field strength is approximately constant and equal to the acceleration of free fall

  5. define gravitational potential at a point as the work done per unit mass by an external force in bringing a small test mass from infinity to that point

  6. solve problems using the equation φ = − GM/r for the gravitational potential in the field due to a point mass

  7. show an understanding that that the gravitational potential energy of a system of two point masses is U = − GMm/r

  8. recall that gravitational field strength at a point is equal to the negative potential gradient at that point and use this to solve problems

  9. analyse problems related to escape velocity by considering energy stores and transfers

  10. analyse circular orbits in inverse square law fields by relating the gravitational force to the centripetal acceleration it causes

  11. show an understanding of satellites in geostationary orbit and their applications.