# Physics Topic: Gravitation

1. Show an understanding of the concept of a gravitational field as an example of field of force and define gravitational field strength as force per unit mass.

2. Recall and use Newton’s law of gravitation in the form F = GMm/r2.

3. Derive, from Newton’s law of gravitation and the definition of the gravitational field strength, the equation for the gravitational field strength g = GM/r2 of a point mass.

4. Recall and apply the equation for the gravitational field strength of a point mass to new situations or to solve related problems.

5. Show an appreciation that on the surface of the Earth g is approximately constant and equal to the acceleration of free fall.

6. Define potential at a point as the work done in bringing unit mass from infinity to the point.

7. Solve problems using the equation for the potential GM/r in the field of a point mass.

8. Recognise the analogy between certain qualitative and quantitative aspects of gravitational and electric fields.

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

10. Show an understanding of geostationary orbits and their application.