Gravitational force between a planet and its moonThe gravitational force that a moon experiences as it orbits around a planet is, \( \large \vec{F} =-\frac{Gm_1m_2}{|\vec{r}_2-\vec{r}_1 |^2}\hat{r}_{1\rightarrow 2} \) [N]. Here $G$ = 6.6726×10-11 N m²/kg² is the gravitational constant, $m_1$ = 6×1024 kg is the mass of the planet, $m_2$ = 8×1021 kg is the mass of the moon, and $\vec{r}_{1\rightarrow 2}$ is the unit vector pointing from the planet towards the moon. The position of the planet is, $\vec{r}_1 = 3\times 10^{8}\hat{x}+2\times 10^{7}\hat{y}+3\times 10^{8}\hat{z}$ [m], and the position of the moon is, $\vec{r}_2 = -3\times 10^{8}\hat{x}+3\times 10^{6}\hat{y}-2\times 10^{7}\hat{z}$ [m]. |