<Kepler's third law> for two <point masses> in a <Newtonian gravitational field> is
$$
\boxed{P^2=\frac{4\pi^2a^3}{G(M_1+M_2)}.}
$$
Here $a$ is the <semimajor axis> of their relative <orbit>, $P$ the <orbital period> and $G$ the <gravitational constant>. Equivalently $(P/\mathrm{yr})^2=(a/\mathrm{AU})^3/[(M_1+M_2)/M_\odot]$, to the accuracy with which these astronomical units normalize the <solar mass>.

Solution

Past exam of the short options paper shared by Parts A and B of the physics course of the University of Oxford / 2019 / S2 / 1 / a / Solution

 Solution (source code)