Physics 9702 · AS & A Level · Gravitational force between point masses
Gravitational force between point masses — practice question
A planet with mass $m$ moves in a circular orbit of radius $r$ around the Sun, which has mass $M$, as shown in Fig. 1.1. The planet’s angular velocity magnitude and its orbital period are $\omega$ and $T$ respectively.
(a(i))[2]
State the meaning of angular velocity.
(a(ii))[1]
State the relation between $\omega$ and $T$.
(b)[4]
Show that, for a planet in a circular orbit of radius $r$, the orbital period $T$ is given by $T^{2} = cr^{3}$, where $c$ is a constant. Explain your working.
(c(i))[2]
Use the expression in (b) to work out the value of $T$ for Neptune.
(c(ii))[2]
Find the linear speed of Venus in its orbit.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “rate of change of angle / angular displacement swept out by radius” …