1. What does a "statically determinate" truss mean?
A. The truss can be solved using equilibrium equations alone
B. The truss requires additional constraints to solve
C. The truss has more unknown forces than equations
D. The truss is inherently unstable
Answer: A) The truss can be solved using equilibrium equations alone
Rationale: A statically determinate truss has enough equations of equilibrium to solve for all
unknown forces, making it stable and solvable without needing additional analysis.
2. If a truss has 6 joints and 9 members, how many reactions will the truss have at the supports in
a 2D plane?
A. 1
B. 2
C. 3
D. 4
Answer: B) 2
Rationale: Using the equation m=2j−3m = 2j - 3m=2j−3, we can calculate the number of
members for a stable truss. With 6 joints, the number of members needed for stability is
2×6−3=92 \times 6 - 3 = 92×6−3=9, which implies that there are two reactions at the supports.
,3. Which of the following is used to calculate the deflection of a truss?
A. Mohr’s Circle
B. Superposition principle
C. Timoshenko beam theory
D. Truss stiffness matrix
Answer: B) Superposition principle
Rationale: The superposition principle is often used to calculate deflections in trusses by
considering the effect of individual forces or moments on the structure.
4. What is the degree of indeterminacy for a truss that is over-constrained (i.e., more members
than required)?
A. 1
B. 2
C. 3
D. Indeterminate
Answer: D) Indeterminate
Rationale: An over-constrained truss has more members than the stability equation allows,
making it statically indeterminate. Solving for forces requires considering material properties and
deformations.
, 5. In a planar truss, what is the characteristic of an unstable truss?
A. The number of members is less than 2j - 3
B. The number of members is greater than 2j - 3
C. The truss has redundant supports
D. The truss has a perfect triangular shape
Answer: A) The number of members is less than 2j - 3
Rationale: If the number of members is less than the minimum required by the stability equation,
the truss is unstable and cannot resist loads properly.
6. What is the primary purpose of a truss in structural design?
A. To increase the strength of the structure
B. To support the roof and floor loads
C. To reduce material consumption
D. To resist shear forces
Answer: B) To support the roof and floor loads
Rationale: Trusses are primarily used in roofs and floors to distribute loads, reduce material
usage, and provide stability.
7. When calculating the internal forces in a truss using the method of joints, what equilibrium
equation is typically used?
A. ΣFy=0\Sigma F_y = 0ΣFy=0 and ΣFx=0\Sigma F_x = 0ΣFx=0
A. The truss can be solved using equilibrium equations alone
B. The truss requires additional constraints to solve
C. The truss has more unknown forces than equations
D. The truss is inherently unstable
Answer: A) The truss can be solved using equilibrium equations alone
Rationale: A statically determinate truss has enough equations of equilibrium to solve for all
unknown forces, making it stable and solvable without needing additional analysis.
2. If a truss has 6 joints and 9 members, how many reactions will the truss have at the supports in
a 2D plane?
A. 1
B. 2
C. 3
D. 4
Answer: B) 2
Rationale: Using the equation m=2j−3m = 2j - 3m=2j−3, we can calculate the number of
members for a stable truss. With 6 joints, the number of members needed for stability is
2×6−3=92 \times 6 - 3 = 92×6−3=9, which implies that there are two reactions at the supports.
,3. Which of the following is used to calculate the deflection of a truss?
A. Mohr’s Circle
B. Superposition principle
C. Timoshenko beam theory
D. Truss stiffness matrix
Answer: B) Superposition principle
Rationale: The superposition principle is often used to calculate deflections in trusses by
considering the effect of individual forces or moments on the structure.
4. What is the degree of indeterminacy for a truss that is over-constrained (i.e., more members
than required)?
A. 1
B. 2
C. 3
D. Indeterminate
Answer: D) Indeterminate
Rationale: An over-constrained truss has more members than the stability equation allows,
making it statically indeterminate. Solving for forces requires considering material properties and
deformations.
, 5. In a planar truss, what is the characteristic of an unstable truss?
A. The number of members is less than 2j - 3
B. The number of members is greater than 2j - 3
C. The truss has redundant supports
D. The truss has a perfect triangular shape
Answer: A) The number of members is less than 2j - 3
Rationale: If the number of members is less than the minimum required by the stability equation,
the truss is unstable and cannot resist loads properly.
6. What is the primary purpose of a truss in structural design?
A. To increase the strength of the structure
B. To support the roof and floor loads
C. To reduce material consumption
D. To resist shear forces
Answer: B) To support the roof and floor loads
Rationale: Trusses are primarily used in roofs and floors to distribute loads, reduce material
usage, and provide stability.
7. When calculating the internal forces in a truss using the method of joints, what equilibrium
equation is typically used?
A. ΣFy=0\Sigma F_y = 0ΣFy=0 and ΣFx=0\Sigma F_x = 0ΣFx=0
