A composite beam is made by attaching the timber and steel portions shown with bolts of 12.7-mm diameter spaced longitudinally every 152.4mm. The modulus of elasticity is 10.5 GPa for the wood and 200 GPa for the steel. For a vertical shear of 5.2 kN, determine (a) the average shearing stress in the bolts, (b) the shearing stress at the center of the cross section. 63.5 101.6 mm 63.5 mm 6.5 mm 139.4 mm 6.5 mm