Prob. 1-34 1-35. If the material fails when the average normal stress reaches 120 psi, determine the largest centrally applied vertical load P the block can support. *1-36. If the block is subjected to a centrally applied force of P = 6 kip, determine the average normal stress in the material. Show the stress acting on a differential volume element of the material. 1 in. 1 in. 4 in. P 1 in. 12 in. 1 in. Probs. 1-35/36