Advanced Higher Physics

Mandatory Course Key Areas - Aug 2018

Conversion between astronomical units (AU) and metres and between light-years (ly) and metres.

Definition of gravitational field strength as the gravitational force acting on a unit mass.

Sketch of gravitational field lines and field line patterns around astronomical objects and astronomical systems involving two objects.

Use of an appropriate relationship to carry out calculations involving gravitational force, masses, and their separation.

F=\frac{\mathrm{GMm}}{r^2}

Use of appropriate relationships to carry out calculations involving period of satellites in circular orbit, masses, orbit radius, and satellite speed.

F=\frac{\mathrm{GMm}}{r^2}=\frac{{\mathrm{mv}}^2}{r}={\mathrm{mr\omega }}^2=\mathrm{mr}{\left(\frac{\mathrm{2\pi }}{T}\right)}^2

Definition of the gravitational potential of a point in space as the work done in moving unit mass from infinity to that point.

Knowledge that the energy required to move mass between two points in a gravitational field is independent of the path taken.

Use of appropriate relationships to carry out calculations involving gravitational potential, gravitational potential energy, masses, and their separation.

$$\begin{gathered} V=-\frac{\mathrm{GM}}{r} \\ {E}_p=\mathrm{Vm}=-\frac{\mathrm{GMm}}{r} \end{gathered}$$

Definition of escape velocity as the minimum velocity required to allow a mass to escape a gravitational field to infinity, where the mass achieves zero kinetic energy and maximum (zero) potential energy.

Derivation of the relationship v_{\mathrm{esc}}=\sqrt{\frac{\mathrm{2GM}}{r}}

Use of an appropriate relationship to carry out calculations involving escape velocity, mass, and distance.

v_{\mathrm{esc}}=\sqrt{\frac{\mathrm{2GM}}{r}}