Which of the following is the primary function of a key in mechanical design?
Answer: A
A key is a mechanical element that prevents relative rotational motion between a shaft and a hub or pulley by transmitting torque.
Q.2Easy
In gear design, what does the term 'Module' represent?
Answer: A
Module is defined as the ratio of pitch circle diameter to the number of teeth (m = D/N). It determines the size of the gear teeth.
Q.3Easy
Which bearing type is most suitable for high-speed applications with moderate loads?
Answer: B
Deep groove ball bearings are ideal for high-speed applications with moderate radial and axial loads due to their low friction and good precision.
Q.4Easy
Which type of fit is used when a permanent assembly is required with no relative motion?
Answer: B
Interference fit (or press fit) results in permanent assembly with no relative motion, as the hole size is smaller than the shaft size, creating an interference.
Q.5Easy
Which material property is MOST critical for designing a component subjected to cyclic loading?
Answer: B
For cyclic loading, fatigue strength and endurance limit are critical as they define the maximum stress that can be applied indefinitely without failure.
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Q.6Easy
In a welded joint, which type of stress is primarily responsible for failure in a butt weld under tensile loading?
Answer: B
In butt welds under tensile loading, direct tensile stress perpendicular to the weld throat is the primary failure mode. The joint must be designed to resist this normal stress effectively.
Q.7Easy
In journal bearing design, if the bearing length is doubled while keeping other parameters constant, how does the load capacity change?
Answer: A
Load capacity in journal bearings is directly proportional to bearing length. Doubling the length doubles the total load-carrying area, thereby doubling the load capacity.
Q.8Easy
Which of the following is the primary function of a Woodruff key in shaft design?
Answer: C
Woodruff keys are semi-circular keys that transmit torque between shaft and hub while providing advantages in manufacturing and maintenance due to their design that allows for easier replacement.
Q.9Easy
In clutch design, what is the primary advantage of a multi-plate clutch over a single-plate clutch?
Answer: C
Multi-plate clutches have multiple contact surfaces, providing significantly higher torque transmission capacity in the same axial space, making them ideal for high-power applications with space constraints.
Q.10Easy
Which of the following is the primary function of a flexible coupling in machine design?
Answer: B
Flexible couplings are designed to accommodate angular, parallel, and axial misalignments while reducing shock loads and vibrations transmitted between shafts.
Q.11Easy
In belt drive design, if the velocity ratio is 3:1 and the smaller pulley has a diameter of 100 mm, what should be the diameter of the larger pulley?
Answer: B
Velocity ratio = D₂/D₁ = N₁/N₂. Therefore, 3 = D₂/100, giving D₂ = 300 mm
Q.12Easy
In spur gear design, the module is 4 mm and the number of teeth on the pinion and gear are 20 and 60 respectively. What is the center distance between the gears?
Answer: B
Center distance = (m × (T₁ + T₂))/2 = (4 × (20 + 60))/2 = 160 mm
Q.13Easy
Which of the following materials is BEST suited for manufacturing hydraulic cylinder pistons?
Answer: C
Stainless steel provides excellent corrosion resistance, high strength, and better sealing properties in hydraulic applications compared to other options.
Q.14Easy
In a worm gear drive with a single-start worm, module 2 mm, and 40 teeth on the gear, what is the worm pitch?
Answer: A
For a worm gear, pitch = module × number of starts = 2 × 1 = 2 mm (for a single-start worm)
Q.15Easy
A hollow shaft has an outer diameter of 60 mm and inner diameter of 40 mm. What is the polar moment of inertia of the shaft?
Which type of bearing is preferred for applications requiring self-alignment capability?
Answer: B
Spherical roller bearings have a spherical outer raceway that allows self-alignment up to 2-3 degrees, making them ideal for misaligned shaft applications.
Q.17Easy
In a spur gear design, what is the primary function of backlash?
Answer: B
Backlash is intentionally provided to accommodate thermal expansion, manufacturing errors, and to prevent gear jamming.
Q.18Easy
Which of the following materials is preferred for manufacturing flexible couplings?
Answer: B
Elastomeric materials in flexible couplings provide damping, shock absorption, and vibration isolation capabilities.
Q.19Easy
A journal bearing is subjected to a radial load of 10 kN with shaft speed of 600 rpm. If bearing length is 80 mm and shaft diameter is 50 mm, find the bearing pressure (Hertzian pressure approximation).
