0.14 linear elastic 0.12 0.08 0.06 0.04 rubber elastic 0.02 5 20. Give the relation for strain energy in a rubber as a function of the extension ratios, and from this develop equations governing the extension ratio and the engineering stress for uniaxial tension 21. Draw plots of modulus versus temperature for various polymers: amorphous, crystalline, crosslinked, non-crosslinked. Explain why the plots have the shape they do. For the three-element spring- dashpot model below (a) Sketch the relaxation and compliance functions Grel(t) and Ucrp(t) tall ithout (b) Develop the differential equation for the model, and solve it for elaxation Grel(t) rive (or at least set up) the expression for the complex modulus of the model 22. Explain the significance of the termscomplex modulus,storage oau⊥usr 23. What is the rationale for claiming that the presence of a low temperature loss peak is a necessary and sufficient condition for good room-temperature impact strength?20. Give the relation for strain energy in a rubber as a function of the extension ratios, and from this develop equations governing the extension ratio and the engineering stress for uniaxial tension. 21. Draw plots of modulus versus temperature for various polymers: amorphous, crystalline, crosslinked, non-crosslinked. Explain why the plots have the shape they do. For the three-element spring- dashpot model below: (a) Sketch the relaxation and compliance functions Grel(t) and Jcrp(t) conceptually, without recourse to equations. (b) Develop the differential equation for the model, and solve it for relaxation Grel(t). (c) Derive (or at least set up) the expression for the complex modulus of the model. 22. Explain the significance of the terms “complex modulus,” “storage modulus,” “loss modulus.” 23. What is the rationale for claiming that the presence of a low- temperature loss peak is a necessary and sufficient condition for good room-temperature impact strength?