A rectangular piece of wood, 50 mm by 100 mm in cross section, is used as a compression block as shown in Fig. P-121. Determine the maximum axial force P which can be safely applied to the block if the compressive stress in the wood is limited to 20 MN/m² and the shearing stress parallel to the grain is limited to 5 MN/m². The grain makes an angle of 20° with the horizontal, as shown. (Hint: Use the results of Problem 120.) Ans. P=77.8 kN 100 mm 20°