ENGR 0022
Materials: Structure and Properties
Exam 1
Fall 2025
Name (print): ______________________________________________
• Exam must be completed in 50 minutes
• Closed book (no phones)
I have neither given nor received unauthorized assistance on this test:
Signature: ________________________________________________
, Section 1: True/False (2 points each, 20 points total)
Circle the correct answer.
T F 1. It is not possible to determine accurately the density of a piece of an unidentified
material unless the volume is known. The volume is not needed for the double
weighing method.
T F 2. In the linear elastic regime, the stored elastic energy per unit volume of a material is
proportional to the square of the strain.
T F 3. The elastic modulus of a material is independent of the applied stress.
T F 4. Thermoplastic polymers have relatively low values of elastic modulus because the
carbon-carbon bonds in the molecules are not as stiff as bonds in metals or ceramics.
The low values of elastic modulus are due to the intermolecular bonds.
T F 5. The FCC crystal structure contains 4 tetrahedral interstitial sites in its unit cell. There
are 8 tetrahedral interstitial sites in the FCC unit cell.
T F 6. The density of a closed cell foam measured using the double weighing method will be
lower than the density of an open cell foam if the volume fraction of pores is the same
in both cases.
T F 7. The maximum elastic modulus of a composite containing aligned fibers can be
determined by the rule of mixtures.
T F 8. The density of a pure element can be accurately calculated as long as the atomic
radius and the atomic mass are known. The crystal structure is also needed.
T F 9. Crystalline materials always have a glass transition temperature. Crystalline
materials have melting points, not glass transition temperatures.
T F 10. Thermoset polymers and elastomers are always amorphous (non-crystalline).
Materials: Structure and Properties
Exam 1
Fall 2025
Name (print): ______________________________________________
• Exam must be completed in 50 minutes
• Closed book (no phones)
I have neither given nor received unauthorized assistance on this test:
Signature: ________________________________________________
, Section 1: True/False (2 points each, 20 points total)
Circle the correct answer.
T F 1. It is not possible to determine accurately the density of a piece of an unidentified
material unless the volume is known. The volume is not needed for the double
weighing method.
T F 2. In the linear elastic regime, the stored elastic energy per unit volume of a material is
proportional to the square of the strain.
T F 3. The elastic modulus of a material is independent of the applied stress.
T F 4. Thermoplastic polymers have relatively low values of elastic modulus because the
carbon-carbon bonds in the molecules are not as stiff as bonds in metals or ceramics.
The low values of elastic modulus are due to the intermolecular bonds.
T F 5. The FCC crystal structure contains 4 tetrahedral interstitial sites in its unit cell. There
are 8 tetrahedral interstitial sites in the FCC unit cell.
T F 6. The density of a closed cell foam measured using the double weighing method will be
lower than the density of an open cell foam if the volume fraction of pores is the same
in both cases.
T F 7. The maximum elastic modulus of a composite containing aligned fibers can be
determined by the rule of mixtures.
T F 8. The density of a pure element can be accurately calculated as long as the atomic
radius and the atomic mass are known. The crystal structure is also needed.
T F 9. Crystalline materials always have a glass transition temperature. Crystalline
materials have melting points, not glass transition temperatures.
T F 10. Thermoset polymers and elastomers are always amorphous (non-crystalline).
