1. Which of the following is the primary purpose of a key in a shaft
assembly?
A. To prevent axial movement of the shaft
B. To prevent the shaft from rotating
C. To transmit torque between the shaft and the component
D. To secure the bearing on the shaft
Answer: C) To transmit torque between the shaft and the component
Rationale: Keys are used in shaft assemblies to transmit torque between
the shaft and the components such as pulleys, gears, and couplings,
ensuring that both parts rotate together.
2. The bending stress in a beam can be found using which of the
following formulas?
A. σ=MI×y\sigma = \frac{M}{I} \times yσ=IM×y
B. σ=MI×x\sigma = \frac{M}{I} \times xσ=IM×x
,C. σ=FA\sigma = \frac{F}{A}σ=AF
D. σ=MI×d\sigma = \frac{M}{I} \times dσ=IM×d
Answer: A) σ=MI×y\sigma = \frac{M}{I} \times yσ=IM×y
Rationale: The bending stress formula σ=MI×y\sigma = \frac{M}{I}
\times yσ=IM×y relates the stress to the moment MMM, the moment
of inertia III, and the distance from the neutral axis yyy.
3. Which of the following materials is most commonly used for
manufacturing gears?
A. Cast Iron
B. Steel
C. Aluminum
D. Copper
Answer: B) Steel
Rationale: Steel, particularly hardened steel, is the most commonly
used material for gears due to its strength, durability, and ability to
withstand wear under heavy loads.
,4. The factor of safety in design is the ratio of:
A. Ultimate stress to yield stress
B. Yield stress to the working stress
C. Working stress to yield stress
D. Ultimate stress to working stress
Answer: B) Yield stress to the working stress
Rationale: The factor of safety (FoS) is the ratio of the material’s yield
stress to the working stress, ensuring that the design operates safely
under load conditions.
5. Which type of bearing is suitable for high radial loads but not for
axial loads?
A. Thrust bearing
B. Journal bearing
C. Roller bearing
D. Ball bearing
, Answer: C) Roller bearing
Rationale: Roller bearings are designed to carry high radial loads, but
they are not suitable for axial loads. For axial loads, thrust bearings are
more appropriate.
6. In machine design, a fatigue failure is most likely to occur due to:
A. Steady and constant loads
B. Variable loading cycles
C. High temperature exposure
D. Low load conditions
Answer: B) Variable loading cycles
Rationale: Fatigue failures occur due to repeated or fluctuating stresses
over time. These stresses, even if they are below the material’s ultimate
tensile strength, can cause crack initiation and growth leading to
failure.
7. The term ‘modulus of resilience’ refers to:
assembly?
A. To prevent axial movement of the shaft
B. To prevent the shaft from rotating
C. To transmit torque between the shaft and the component
D. To secure the bearing on the shaft
Answer: C) To transmit torque between the shaft and the component
Rationale: Keys are used in shaft assemblies to transmit torque between
the shaft and the components such as pulleys, gears, and couplings,
ensuring that both parts rotate together.
2. The bending stress in a beam can be found using which of the
following formulas?
A. σ=MI×y\sigma = \frac{M}{I} \times yσ=IM×y
B. σ=MI×x\sigma = \frac{M}{I} \times xσ=IM×x
,C. σ=FA\sigma = \frac{F}{A}σ=AF
D. σ=MI×d\sigma = \frac{M}{I} \times dσ=IM×d
Answer: A) σ=MI×y\sigma = \frac{M}{I} \times yσ=IM×y
Rationale: The bending stress formula σ=MI×y\sigma = \frac{M}{I}
\times yσ=IM×y relates the stress to the moment MMM, the moment
of inertia III, and the distance from the neutral axis yyy.
3. Which of the following materials is most commonly used for
manufacturing gears?
A. Cast Iron
B. Steel
C. Aluminum
D. Copper
Answer: B) Steel
Rationale: Steel, particularly hardened steel, is the most commonly
used material for gears due to its strength, durability, and ability to
withstand wear under heavy loads.
,4. The factor of safety in design is the ratio of:
A. Ultimate stress to yield stress
B. Yield stress to the working stress
C. Working stress to yield stress
D. Ultimate stress to working stress
Answer: B) Yield stress to the working stress
Rationale: The factor of safety (FoS) is the ratio of the material’s yield
stress to the working stress, ensuring that the design operates safely
under load conditions.
5. Which type of bearing is suitable for high radial loads but not for
axial loads?
A. Thrust bearing
B. Journal bearing
C. Roller bearing
D. Ball bearing
, Answer: C) Roller bearing
Rationale: Roller bearings are designed to carry high radial loads, but
they are not suitable for axial loads. For axial loads, thrust bearings are
more appropriate.
6. In machine design, a fatigue failure is most likely to occur due to:
A. Steady and constant loads
B. Variable loading cycles
C. High temperature exposure
D. Low load conditions
Answer: B) Variable loading cycles
Rationale: Fatigue failures occur due to repeated or fluctuating stresses
over time. These stresses, even if they are below the material’s ultimate
tensile strength, can cause crack initiation and growth leading to
failure.
7. The term ‘modulus of resilience’ refers to:
