The stress-deflection characteristics of two cushioning materials are shown below. 250 200 150 100 50 wwwww 5 10 15 Deflection (mm) 20 25 30 a) One of the materials is a compliant polyurethane open cell foam and the other is multi-layered corrugated paperboard. Using the line colours, identify which is which. b) Assuming that the cross-sectional area of the multi-layered corrugated paperboard cushion is 0.01 m, produce a fully-labelled strain energy vs deflection curve for the multi-layered corrugated paperboard cushion. c) Assuming that the cross-sectional area of the multi-layered corrugated paperboard cushion is 0.01 m, produce a fully-labelled graph of peak acceleration vs impact velocity for a 40 kg mass as a function of d) If the maximum deflection measured during a drop test of a 40 kg mass in the multi-layered corrugated paperboard was 10 mm, determine the peak Stress (in kPa) generated by the collision. e) For the case above, determine the peak collision acceleration in m/s if the contact area between the mass and the cushion was 0.01 m.