The designers of lamp mechanisms, such as that shown in the figure, usually rely on joint friction to aid in maintaining static equilibrium. For the pres- ent problem, assume that sufficient friction exists at point C to prevent rotation there, but ignore fric- tion at all other joints. If the mass of the lamp fix- ture is 0.6 kg with mass center at G, determine the spring force Fs necessary for equilibrium in the position shown. www. 225 mm E 65 mm 15 225 mm Problem 4/117 60 60 mm mm B D C G