$7\mathrm{.}1\mathrm{.}21.[$Level $3]$ The illustration shows a hunting stand that a bow hunter has built from which to target deer. A couple of civic$-$minded squirrels removed the nails holding the stand to the tree, and since hunters are poor carpenters in general, the insufficiently reinforced stand immediately began falling to the side. The illustration shows the stand when $\backslash (\backslash$theta$=60^\{\backslash$circ$\}\backslash )$ and $\backslash (\backslash$theta$=-0\mathrm{.}936\backslash$mathrm$\{$rad$\}/\backslash$mathrm$\{$s$\}.$ m$=15\backslash$mathrm$\{$~kg$\}\backslash ).$ Model the connections at $\backslash ($ A$,$ B$,$ C $\backslash ),$ and $\backslash ($ D $\backslash )$ as frictionless pivots and treat the supports as massless, rigid links.

E$7\mathrm{.}1\mathrm{.}21$

a$.$ What forces are the supports supplying to the stand's floor at the instant shown in $($b$)?$

b$.$ What is $\backslash (\backslash$theta $\backslash )$ equal to$?$

c$.$ How do the results compare to the problem of an inverted pendulum $($shown in $($c$))$ that's tipped over from the upright $($unstable$)$ equilibrium?