One end of the torsion spring is secured to the ground at A, and the other end is fastened to the shaft at B. The torsional stiffness K of the elastic spring is the torque required to twist the spring through an angle of one radian.
The spring resists the moment about the shaft axis caused by the tension mg in the cable wrapped around the drum of radius r.
Determine the equilibrium value of h measured from the dashed position, where the spring is untwisted.
