A certain children's building block is comprised of a square prism of side length b. Atop the block are four pegs that are used to connect multiple blocks together, by inserting the pegs into corresponding holes on the bottom of the block. Assume that the pegs make perfect contact with the corresponding holes. The top surface of each peg does not contact the top of the corresponding hole. Bob has stacked two of these blocks together and must exert a force F to pull them apart. a) Draw a free body diagram that shows the shear forces acting on a single block. (0.5 marks) b) Considering only the lower block, what is the total area that is subjected to shear force? (0.25 marks) c) What is the average shear stress acting on the lower block? (0.75 marks) 08 d) What is the maximum average normal stress experienced by a single peg? (1 mark) F b Th 10 Use the following values in your working out: F = 12 N b = 13 mm a = 4 mm h = 5 mm F