This text is usually replaced by the Flash movie.
$O$ is the centre of the balance, and $X$ is the position of
the initially empty hook.
If you leave the hook at $X$ empty, what angle does $OX$ make to
the vertical once the balance settles?
If you were to attach a weight of $1$ unit at $X$ , what do you
think the angle might be?
Were you right?
If you were to attach a weight of $2$ units at $X$ what do you
think the angle might be?
Right that time?
You only need the $1$ and $2$ unit weights for the problem set but
the others are there to let you explore, conjecture and test - have
fun.