# A balanced lever has two weights on it, the first with mass 16 kg  and the second with mass 36 kg. If the first weight is  2 m from the fulcrum, how far is the second weight from the fulcrum?

Feb 16, 2016

$0.889 m$
From the second condition of static equilibrium, the resultant torque must be zero, ie $\sum \vec{\tau} = 0$ where $\vec{\tau} = \vec{r} \times \vec{F}$.
$\therefore {r}_{1} {F}_{1} - {r}_{2} {F}_{2} = 0$
$\therefore \left(2 \times 16 g\right) - {r}_{2} \times 36 g = 0$
$\therefore {r}_{2} = 0.889 m$.