Explore topic-wise MCQs in Machine Design.

This section includes 104 Mcqs, each offering curated multiple-choice questions to sharpen your Machine Design knowledge and support exam preparation. Choose a topic below to get started.

1.

Fatigue life of a material for a fully reversed loading condition is estimated from a = 1100 N 0.15 where a is the stress amplitude in MPa and N is the failure life in cycles. The maximum allowable stress amplitude (in MPa) for a life of 1 105 cycles under the same loading condition is_______(correction to two decimal places).

A. 195.61 N
B. 194.61 N
C. 193.61 N
D. 192.61 N
Answer» B. 194.61 N
Discussion
2.

For ball bearings, the fatigue life L measured in number of revolutions and the radial load P are related by FL1/3 = K, where K is a constant. It withstands a radial load of 2 kN for a life of 540 million revolutions. The load (in kN) for a life of one million revolutions is ______.

A. 16.2865 kN
B. 18 kN
C. 15 kN
D. 15.2865 kN
Answer» B. 18 kN
Discussion
3.

Z2 and Z4 are

A. 64 and 45
B. 45 and 64
C. 48 and 60
D. 60 and 48
Answer» B. 45 and 64
Discussion
4.

Ball bearings are rated by a manufacturer for a life of 106 revolutions. The catalogue rating of a particular bearing is 16 kN. If the design load is 2 kN, the life of the bearing will be P x 106 revolutions, where P is equal to _________

A. 2/5
B. 5/2
C. 4/3
D. 3/4
Answer» C. 4/3
Discussion
5.

A self-aligning ball bearing has a basic dynamic load rating (C10, for 106 revolutions) of 35 kN. If the equivalent radial load on the bearing is 45 kN, the expected life (in 106 revolutions) is

A. below 0.5
B. 0.5 to 0.8
C. 0.8 to 1.0
D. above 1.0
Answer» B. 0.5 to 0.8
Discussion
6.

At a critical point in a component, the state of stress is given as xx = 100 MPa, yy = 220 MPa, xy = yx = 80 M Pa and al l ot her st r ess components are zero. The yield strength of the material is 468 MPa. The factor of safety on the basis of maximum shear stress theory is_____ (round off to one decimal place).

A. 1.8
B. 1.4
C. 2.8
D. 2.4
Answer» B. 1.4
Discussion
7.

A machine element is subjected to the following bi-axial state of stress; x = 80 MPa; y = 20 MPa; x = 40 MPa. If the shear strength of the material is 100 MPa, the factor of safety as per Tresca's maximum shear stress theory is

A. 1.0
B. 2.0
C. 2.5
D. 3.3
Answer» C. 2.5
Discussion
8.

Match the rolling element bearings with the most appropriate loading condition
Bearing-typeLoading condition
(a) Ball bearing (p) Tangential load
(b) Roller bearing (q) Radial load
(c) Needle bearing(r) Heavy radial load with impact
(d) Taper roller bearing(s) Light radial load with space limitation
(t) Heavy radial and axial load
(u) Fatigue load

A. a p, b r, c s, d q
B. a r, b p, c s, d t
C. a q, b r, c s, d t
D. a p, b r, c t, d s
Answer» D. a p, b r, c t, d s
Discussion
9.

Match the type of gears with their most appropriate description.
Type of gearsDescription
P. Helical1. Axes non parallel and non intersecting
Q. Spiral Bevel2. Axes parallel and teeth are inclined to the axis
R. Hypoid3. Axes parallel and teeth are parallel to the axis
S. Rack and pinion4. Axes are perpendicular and intersecting, and teeth are inclined to the axis
5. Axes are perpendicular and used for large speed reduction
6. Axes parallel and one of the gears has infinite radius
A. P 2, Q 4, R 1, S 6
B. P 1, Q 4, R 5, S 6
C. P 2, Q 6, R 4, S 2
D. P 6, Q 3, R 1, S 5
Answer» B. P 1, Q 4, R 5, S 6
Discussion
10.

Match the following
Type of gearsArrangement of shafts
P. Bevel gears1.Nonparallel offset shafts
Q. Worm gears2.Nonparallel intersecting shafts
R. Herringbone 3. Nonparallel, non -intersecting shafts
S. Hypoid gears4.Parallel shafts
A. P 4, Q 2, R 1, S 3
B. P 2, Q 3, R 4, S 1
C. P 3, Q 2, R 1, S 4
D. P 1, Q 3, R 4, S 2
Answer» C. P 3, Q 2, R 1, S 4
Discussion
11.

A ductile material having an endurance limit of 196 N/mm2 and the yield point at 294 N/ mm2 is stressed under variable load. The maximum and minimum stresses are 147 N/ mm2 and 49 N/mm2. The fatigue stress concentration factor is 1.32. The available factor of safety for this loading is

A. 3.0
B. 1.5
C. 1.33
D. 4.0
Answer» C. 1.33
Discussion
12.

For the given statements :
I. Mating spur gear teeth is an example of higher pair
II. A revolute Joint is an example of lower pair Indicate the correct answer.

A. Both I and II are false
B. I is true and II is false
C. I is false and II is true
D. Both I and II are true
Answer» E.
Discussion
13.

A bar is subjected to fluctuating tensile load from 20 kN to 100 kN. The material has yield strength of 240 MPa and endurance limit in reversed bending is 160 MPa. According to the Soderberg principle, the area of cross-section in mm2 of the bar for a factor of safety of 2 is

A. 400
B. 600
C. 750
D. 1000
Answer» E.
Discussion
14.

A forged steel link with uniform diameter of 30 mm at the centre is subjected to an axial force that varies from 40 kN in compression to 160 kN in tension. The tensile (Su), yield (Sy) and corrected endurance (Se) strengths of the steel material are 600 MPa, 420 MPa and 240 MPa respectively. The factor of safety against fatigue endurance as per Soderberg's criterion is

A. 1.26
B. 1.37
C. 1.45
D. 2.00
Answer» D. 2.00
Discussion
15.

In terms of theoretical stress concentration factor kt and fatigue stress concentration factor kf, the notch sensitivity q is expressed as

A.
B.
C.
Answer» B.
Discussion
16.

A machine component made of a ductile material is subjected to a variable loading with min = 50 MPa and max = 50 MPa. If the corrected endurance limit and the yield strength for the material are e = 100 MPa and for the material are y = 300 MPa, respectively, the factor of safety is __________.

A. 9
B. 2
C. 5
D. 7
Answer» C. 5
Discussion
17.

Match the Following
List-I
(Gear Types)		List-II
(Applications)
A. Worm gears 1. Parallel shafts
B. Cross helical 2. Nonparallel, gears intersecting shafts
C. Bevel gears 3. Nonparallel, nonintersecting shafts
D. Spur gears 4. Large speed ratios

A. A - 2 , B - 3 , C - 4 , D - 1
B. A - 4 , B - 3 , C - 2 , D - 1
C. A - 3 , B - 4 , C - 2 , D - 1
D. A - 1 , B - 3 , C - 4 , D - 2
Answer» C. A - 3 , B - 4 , C - 2 , D - 1
Discussion
18.

Two identical ball bearings Pand Q are operating at loads 30 kN and 45 kN respectively. The ratio of the life of bearing P to the life of bearing Q is

A. 81/16
B. 27/8
C. 9/4
D. 3/2
Answer» C. 9/4
Discussion
19.

Weldments in fabricated steel beams are designed for

A. bending stresses at the flange
B. shear stresses in transverse plane
C. combination of bending and shear
D. none of these because in fabricated beams welds not to get stressed
Answer» D. none of these because in fabricated beams welds not to get stressed
Discussion
20.

In the design of shafts made of ductile materials subjected to twisting moment and bending moment, the recommended theory of failure is

A. maximum principal stress theory
B. maximum principal strain theory
C. maximum shear stress theory
D. maximum strain-energy theory
Answer» D. maximum strain-energy theory
Discussion
21.

The centre distance in the second stage is

A. 90 mm
B. 120 mm
C. 160 mm
D. 240 mm
Answer» C. 160 mm
Discussion
22.

For ball bearings, the fatigue life L measured in number of revolutions and the radial load P are related by FL

A. 16.2865 kN
B. 18 kN
C. 15 kN
D. 15.2865 kN
Answer» B. 18 kN
Discussion
23.

A hydrodynamic Journal bearing is subjected to 2000 N load at a rotational speed of 2000 rpm. Both bearing bore diameter and length are 40 mm. If radial clearance is 20 mm and bearing is lubricated with an oil having viscosity 0.03 Pa.s, the Sommerfeld number of the bearing is __________.

A. 0.6
B. 0.8
C. 8.0
D. 6.0
Answer» C. 8.0
Discussion
24.

Ball bearings are rated by a manufacturer for a life of 106 revolutions. The catalogue rating of a particular bearing is 16 kN. If the design load is 2 kN, the life of the bearing will be P x 10

A. 2/5
B. 5/2
C. 4/3
D. 3/4
Answer» C. 4/3
Discussion
25.

A small element at the critical section of a component in biaxial state of stress with the two principal stresses being 360 MPa and 140 MPa. The maximum working stress according to distortion energy theory is

A. 220 MPa
B. 110 MPa
C. 314 MPa
D. 330 MPa
Answer» D. 330 MPa
Discussion
26.

During a high cycle fatigue test, a metallic specimen is subjected to cyclic loading with a mean stress of + 140 MPa, and a minimum stress of 70 MPa. The R-ratio (minimum stress to maximum stress) for this cycle loading is _______ (round off to one decimal place).

A. 0.1
B. 0.2
C. - 0.1
D. - 0.2
Answer» E.
Discussion
27.

A disc clutch with a single friction surface has coefficient of friction equal to 0.3. The maximum pressure which can be imposed on the friction material is 1.5 MPa. The outer diameter of the clutch plate is 200 mm and its internal diameter is 100 mm. Assuming uniform wear theory for the clutch plate, the maximum torque (in Nm) that can be transmitted is ________.

A. 529 N - m
B. 533 N - m
C. 531.14 N - m
D. 530.14 N - m
Answer» E.
Discussion
28.

A disk clutch is required to transmit 5 kW at 2000 rpm. The disk has a friction lining with coefficient of friction equal to 0.25. Bore radius of friction lining is equal to 25 mm. Assume uniform contact pressure of 1 MPa. The value of outside radius of the friction lining is

A. 39.4 mm
B. 49.5 mm
C. 97.9 mm
D. 142.9 mm
Answer» B. 49.5 mm
Discussion
29.

Twenty degree full depth involute profiled 19- teeth pinion and 37-teeth gear are in mesh. If the module is 5 mm, the center distance between the gear pair will be

A. 140 mm
B. 150 mm
C. 280 mm
D. 300 mm
Answer» B. 150 mm
Discussion
30.

In order to test the efficiency of reducer gear train 1 kW input was given at the input end at a speed of 1440 rpm and at the output end the measured torque was 56.36 Nm. If the ratio of speed reduction in this unit is 10: 1, the efficiency is about

A. 78%
B. 85%
C. 63%
D. 96%
Answer» C. 63%
Discussion
31.

Which of the bearings given below SHOULD NOT be subjected to a thrust load?

A. Deep groove ball bearing
B. Angular contact ball bearing
C. Cylindrical (straight) roller bearing
D. Single row tapered roller bearing
Answer» D. Single row tapered roller bearing
Discussion
32.

A cylindrical shaft is subjected to an alternating stress of 100 MPa. Fatigue strength to sustain 1000 cycles is 490 MPa. If the corrected endurance strength is 70 MPa, estimated shaft life will be

A. 1071 cycles
B. 15000 cycles
C. 281914 cycles
D. 928643 cycles
Answer» D. 928643 cycles
Discussion
33.

A spur gear has a module of 3 mm, number of teeth 16, a face width of 36 mm and a pressure angle of 20 . It is transmitting a power of 3 kW at 20 rev/s. Taking a velocity factor of 1.5 and a form factor of 0.3, the stress in the gear tooth is about

A. 32 MPa
B. 46 MPa
C. 58 MPa
D. 70 MPa
Answer» C. 58 MPa
Discussion
34.

The resultant force on the contacting gear tooth is N is

A. 77.23
B. 212.20
C. 2258.1
D. 289.43
Answer» D. 289.43
Discussion
35.

A band brake having bandwidth of 80 mm, drum diameter of 250 mm, coefficient of friction of 0.25 and angle of wrap of 270 degrees is required to exert a friction torque of 1000 N m. The maximum tension (in kN) developed in the band is

A. 1.88
B. 3.56
C. 6.12
D. 11.56
Answer» E.
Discussion
36.

In spur gears, the circle on which the involute is generated is called the

A. pitch circle
B. clearance angle
C. base circle
D. addendum circle
Answer» D. addendum circle
Discussion
37.

A bar is subjected to fluctuating tensile load from 20 kN to 100 kN. The material has yield strength of 240 MPa and endurance limit in reversed bending is 160 MPa. According to the Soderberg principle, the area of cross-section in mm

A. 400
B. 600
C. 750
D. 1000
Answer» E.
Discussion
38.

A forged steel link with uniform diameter of 30 mm at the centre is subjected to an axial force that varies from 40 kN in compression to 160 kN in tension. The tensile (S

A. 1.26
B. 1.37
C. 1.45
D. 2.00
Answer» D. 2.00
Discussion
39.

A four-wheel vehicle of mass 1000 kg moves uniformly in a straight line with the wheels revolving at 10 rad/s. The wheels are identical, each with a radius of 0.2 m. Then a constant braking torque is applied to all the wheels and the vehicle experience a uniform deceleration. For the vehicle to stop in 10s, the braking torque (in Nm) on each wheel is _______.

A. 19 N - m
B. 15 N - m
C. 10 N - m
D. None of the above
Answer» D. None of the above
Discussion
40.

The minimum number of teeth on the pinion to operate without interference in standard full height involute teeth gear mechanism with 20 pressure angle is

A. 14
B. 12
C. 18
D. 32
Answer» D. 32
Discussion
41.

Large speed reductions (greater than 20) in one stage of a gear train are possible through

A. Spur gearing
B. Worm gearing
C. Bevel gearing
D. Helical gearing
Answer» C. Bevel gearing
Discussion
42.

A 1.5 kW motor is running at 1440 rev/min. It is to be connected to a stirrer running at 36 rev/min. The gearing arrangement suitable for this application is

A. differential gear
B. helical gear
C. spur gear
D. worm gear
Answer» E.
Discussion
43.

To make a worm drive reversible, it is necessary to increase

A. centre distance
B. worm diameter factor
C. number of starts
D. reduction ratio
Answer» D. reduction ratio
Discussion
44.

A lightly loaded full Journal bearing has Journal diameter of 50 mm, bush bore of 50.05 mm and bush length of 20 mm. If rotational speed of Journal is 1200 rpm and average viscosity of liquid lubricant is 0.03 Pa s, the power loss (in W) will be

A. 37
B. 74
C. 118
D. 237
Answer» B. 74
Discussion
45.

A Journal bearing has a shaft diameter of 40 mm and a length of 40 mm. The shaft is rotating at 20 rad/s and the viscosity of the lubricant is 20 mPa.s. The clearance is 0.020 mm. The loss of torque due to the viscosity of the lubricant is approximately

A. 0.040 Nm
B. 0.252 Nm
C. 0.400 Nm
D. 0.652 Nm
Answer» B. 0.252 Nm
Discussion
46.

A natural feed Journal bearing of diameter 50 mm and length 50 mm operating at 20 revolution/sec. carries a load of 2.0 kN. The lubricant used has a viscosity of 20 mPa.s. The radial clearance is 50 m. The Sommerfield number for the bearings is

A. 0.062
B. 0.125
C. 0.250
D. 0.785
Answer» C. 0.250
Discussion
47.

A machine component made of a ductile material is subjected to a variable loading with

A. 9
B. 2
C. 5
D. 7
Answer» C. 5
Discussion
48.

Which theory of failure will you use for aluminium components under steady loading is

A. principal stress theory
B. principal strain theory
C. strain energy theory
D. maximum shear stress theory
Answer» E.
Discussion
49.

Axial operation claw clutches having selflocking tooth profile

A. can be disengaged at any speed
B. can be disengaged onlyunloaded
C. can be engaged only when unloaded
D. can work only with load
Answer» D. can work only with load
Discussion
50.

A pair of spur gears with module 5 mm and a center distance of 450 mm is used for a speed reduction of 5 : 1. The number of teeth on pinion is ______ .

A. 32
B. 30
C. 31.5
D. 32.4
Answer» C. 31.5
Discussion