Problems $21\mathrm{.}6\mathrm{.}3.$

A massless needle is in static equilibrium with two linear springs and a torsional one as shown in Fig$\mathrm{.}21\mathrm{.}8\mathrm{.}14.$ A small rotation $$ is applied to the torsional spring. Find the equivalent torsional elastic constant of this system.

Are the linear springs in series or in parallel? Why?

Figure $21\mathrm{.}8\mathrm{.}14$: Needle connected by springs.