Post-lab questions: 1. Which type of cast iron is ductile in comparison to others? Why? 2. On the basis of microstructure, explain why gray iron is brittle and weak in tension? 3. Compare gray and malleable cast irons with respect to (a) microstructure and (b) mechanical characteristics. 4. On the basis of microstructure, explain why gray iron has an excellent damping ability compare to white cast iron? 5. What is the significance of this experiment? How is it related to your course of study