2.81 Two blocks of rubber, each of width w = 60 mm, are bonded to rigid supports and to the movable plate AB. Knowing that a force of mag- nitude P = 19 kN causes a deflection 8 = 3 mm of plate AB, deter- mine the modulus of rigidity of the rubber used. 35 mm A 35 mm 180 mm Fig. P2.81 and P2.82 P B