d) How does compounding polystyrene with a suitable distribution of rubber particles Improve its properties e) Why does a short-fiber composite have inferior strengths and stiffnesses compared to continuous-fiber composites? f) Why might a plot of E vs. Kle be useful in materials selection?d) How does compounding polystyrene with a suitable distribution of rubber particles improve its properties? e) Why does a short-fiber composite have inferior strengths and stiffnesses compared to continuous-fiber composites? f) Why might a plot of E vs. KIc be useful in materials selection?