## Gravity

Force that drives the universe - attractive force between masses
1 of 4 fundamental forces

$$
{F _{g} }= {{Gm_1m_2}\over{r^2}}
$$

where
$G=$ gravitational constant $=6.67  \times10^{-11}Nm^2kg^{-2}$
$r=$ distance between *centres* of $m_1$ and $m_2$

Area under force-distance graph = work = $\Delta E$

# Newton