4. Which of the below can be true at the same time? And why? A. I only B. Il only C. IV only D. III and IV E. I, III, and IV 1. Velocity: Constant; Acceleration: Constant II. Velocity: Constant; Acceleration: Changing III. Velocity: Changing; Acceleration: Constant IV. Velocity: Changing; Acceleration: Changing

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1. For each, state whether it is TRUE or FALSE, and support your answer with a few sentences or provide a sketch. In rectangular coordinates the unit vectors change with respect to a) time. b) In cases of uniform acceleration, you could define velocity as a function of time or as a function of position. c) If two particles are moving along the same line, you can find the position of B with respect to A by adding xA+xB. The same relationship is true for velocity and acceleration. A B MAY 124 tv A

7. Which of the following is false: a. The coefficient of thermal expansion is larger if the bond energy is smaller b. Ceramics are generally ionic bonding c. Van der Waals bonding is generally stronger than covalent bonding d. The free electrons in metallic bonding is reason for electrical conductivity 8. Which of the following is true: a. Polymers are generally denser than ceranmics b. Young's modulus of ceramics are similar to polymers c. Composites have higher tensile strength than metals d. Ceramics have low resistance to fracture than metals