What is the difference between Thermoplastics and Thermosetpolymers?

A)Thermoplastics can be moulded to shape, thermoset cannot.

B)Thermoplastics have covalent bonds that can be broken andreformed, thermoset does

not.

c. Thermoplastics have entangled polymerics units that can beuntangled at elevated

temperature, thermoset does not.
d. Thermoset plastics are more flexible then thermoplastics.

Q )What is/are the benefit(s) of short fibre reinforcements?

A)Increased stiffness only.

B)Increased strength and increased Toughness.

C) Increased Toughness and increased flexibility.

D) None of the above.

What is apparent density?

a)Density as measured via suspension in water.

b)Density of materials without any pores.

c)Density of material calculated with the inclusion of ONLY openpores.

e)Density of materials calculated with the inclusion of ONLYclose pores.

Q Plane strain fracture toughness is a fundamental materialproperty which:

a) is valid when specimen thickness is much greater than crackdimensions.

b) increases with increasing strain rate and decreasingtemperature.

c)usually increases with strengthening.

d)is not dependent on microstructure

Q)Nickel superalloys are selected for high-temperature gasturbine blades because of:

a)High modulus.

b)High creep strength.

c)High maximum working temperature.

d) b and c.

Q. The most important mechanical properties of metals includestiffness, strength, ductilityand toughness. Which of the followingstatements is true:

a. Both strength and stiffness are strongly dependent onmicrostructure and processing.

b. Strength is a measure of resistance to elastic deformationwhereas toughness is a measure of resistance to fracture.

c. Ductility is a measure of the ability of a material toplastically deform.d. Increasing strength generally increasestoughness.