Practice Sets Mechanical Engineering

112 Pages·2017·3.196 MB·English

by  Prof. Jitendra Mohan

[For Railway & Other Engineering (Diploma)
Competitive Examinations]
By
Prof. Jitendra Mohan
Upkar Prakashan, Agra-2
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ISBN : 978-93-5013-628-7
Code No. 1875
Contents
1. Practice Test Paper-1 .................................................................................................. 3–12
2. Practice Test Paper-2 .................................................................................................. 13–23
3. Practice Test Paper-3 ................................................................................................... 24–33
4. Practice Test Paper-4 .................................................................................................. 34–44
5. Practice Test Paper-5 .................................................................................................. 45–55
6. Practice Test Paper-6 ................................................................................................... 56–66
7. Practice Test Paper-7 ................................................................................................... 67–75
8. Practice Test Paper-8 ................................................................................................... 76–88
9. Practice Test Paper-9 .................................................................................................. 89–98
10. Practice Test Paper-10 ................................................................................................. 99–108
Practice Sets
Mechanical
enGineeRinG
Practice Test Paper–1
1. In a queuing problem, if the arrivals are completely 7. Which one of the following statements is correct?
random, then the probability distribution of number Standard time is obtained from normal time by adding
of arrivals in a given time follows: the policy allowance and:
(a) Poisson distribution (a) personal allowances only
(b) normal distribution (b) fatigue allowances only
(c) binominal distribution (c) delay allowances only
(d) exponential distribution (d) personal, fatigue and delay allowances
2. Consider the following statements in respect of 8. Which one of the following is not a technique under
assignment method of optimization: Predetermined Motion Time System (PMTS)?
1. The matrix format of the method must be a square (a) Work factor
matrix. (b) Synthetic data
(c) Stopwatch time study
2. Some type of rating has to be given to the
(d) MM
performance of each pairing.
9. Which one of the following is not a necessary
Which of the statements given above is/are correct?
information input to Material Requirements
(a) Only 1 (b) Only 2
Planning?
(c) Both 1 and 2 (d) Neither 1 nor 2
(a) Inventory on hand
3. Which one of the following is not the solution method
(b) Bill of materials
of transportation problems?
(c) Sequence of operations on a job
(a) Hungarian method
(d) Master production schedule (MPS)
(b) Northwest corner method
10. If the annual demand of an item becomes half,
(c) Least cost method
ordering cost double, holding cost one-fourth and the
(d) Vogel’s approximation method
unit cost twice, then what is the ratio of the new EOQ
4. In a linear programming problem, if a basic solution
and the earlier EOQ?
has no more than m positive x (j = 1, 2 ,..., n), it is 1
j
(a) 1/2 (b)
called:
2
(a) Basic feasible solution
(c) 2 (d) 2
(b) Unbounded solution.
(c) Non-degenerate basic feasible solution 11. In the ABC method of inventory control, Group A
(d) None of the above constitutes costly items. What is the usual percentage
5. Consider the following statements in respect of PERT of such items of the total items?
and CPM: (a) 10 to 20%
1. PERT is event-oriented while CPM is activity- (b) 20 to 30%
oriented. (c) 30 to 40%
2. PERT is probabilistic while CPM is determinis- (d) 40 to 50%
tic. 12. Which one of the following is an inventory system
3. Levelling and smoothing are the techniques that keeps a running record of the amount in storage
related to resource scheduling in CPM. and replenishes the stock when it drops to a certain
Which of the statements given above are correct? level by ordering a fixed quantity?
(a) 1, 2 and 3 (b) Only 1 and 2 (a) EOQ (b) Periodic
(c) Only 2 and 3 (d) Only 1 and 3 (c) Peripheral (d) ABC
6. In case of solution of linear programming problem 13. In a network, what is total float equal to?
using graphical method, if the constraint line of one (a) LFTj– ESTi + ti – j
of the non-redundant constraints is parallel to the (b) ESTj – LFTi + ti – j
(c) EST – LFT – t
objective function line, then it indicates: i i i – j
(d) LFT – EST – t
(a) an infeasible solution j i i – j
(b) a degenerate solution where, LFT = latest finish time of an activity;
(c) an unbound solution EST = earliest start time of an activity;
(d) a multiple number of optimal solutions t i – j = time of activity i – j
4 Mechanical Engineering
14. Manufacturing a product requires processing on four respectively, then what is the stress produced in the
machines A, B, C, D in the order A – B – C D. The rod?
capacities of four machines are A = 100, B = 110, C (a) 100 MPa (tensile)
= 20 and D = 130 units per shift. If the expected output (b) 200 MPa (tensile)
is 90% of the system capacity, then what is the (c) 200 MPa (compressive)
expected output? (d) 100 MPa (compressive)
(a) 90 units (b) 99 units 21. Fabrication weldability test is used to determine:
(c) 108 units (d) 117 units (a) mechanical properties required for satisfactory
15. If the total investment is Rs 500000 for a target performance of welded joint
production, the income for the current year is Rs (b) susceptibility of welded joint for cracking
300000 and total operating cost is Rs. 100000 ; what (c) suitability for joint design
is the economic yield? (d) appropriate machining process
(a) 10% (b) 30% 22. Which one of the following statements is correct?
(c) 20% (d) 40% Beams of uniform strength vary in section such that:
16. In a Mohr’s circle, the radius of the circle is taken (a) bending moment remains constant
as (b) deflection remains constant
s −s 2 (c) maximum bending stress remains constant
(a)  x y  +(t )2 (d) shear force remains constant.
 2  xy 23. In the case of beams with circular cross-’section, what
(s −s )2 is the ratio of the maximum shear stress to average
(b) x y +(t )2 shear stress?
xy
2 (a) 3 : 1 (b) 2 : 1
(c) 3 : 2 (d) 4 : 3
(s −s )2
(c) x y −(t )2 24. What is the maximum torque transmitted by a hollow
xy
2 shaft of external radius R and internal radius r?
π π
(d) (sx −sy)2+(txy)2 (a) 16(R3−r3)fs (b) 2R(R4−r4)fs
where σ and σ are normal stresses along x and y π π R4−r4 
x y (c) (R4−r4)f (d)   f
directions respectively and σxy is the shear stress. 8R s 32 R  s
17. Disruptive strength is the maximum strength of a ( f = maximum shear stress in the shaft material).
s
metal, when: 25. Consider the following statements at given point in
(a) subjected to 3 principal tensile stresses at right the case of thick cylinder subjected to fluid pressure:
angles to one another and of equal magnitude 1. Radiul stress is compressive
(b) loaded in tension 2. Hoop stress is tensile
(c) loaded in compression 3. Hoop stress is compressive
(d) loaded in shear. 4. Longitudinal stress is tensile and it varies along
18. E, G, K and μ represent the elastic modulus, shear the length
modulus, bulk modulus and Poisson’s ratio respectively 5. Longitudinal stress is tensile and remains constant
of a linearly elastic, isotropic and homogeneous along the length of the cylinder.
material. To express the stress-strain relations Which of the statements given above are correct?
completely for this material, at least: (a) Only 1,2 and 4 (b) Only 3 and 4
(a) E, G and μ must be known (c) Only 1, 2 and 5 (d) Only 1, 3 and 5
(b) E, K and μ must be known 26. Which one of the following welding processes
(c) any two of the four must be known consists of minimum heat affected zone (HAZ)?
(d) all the four must be known (a) Shielded Metal Arc Welding (SWAW)
19. Principal strains at a point are 100 × 10–6 and – 200 (b) Laser Beam Welding (LBW)
× 10–6. What is the maximum shear strain at the (c) Ultrasonic Welding (USW)
point? (d) Metal Inert Gas Welding (MIG)
(a) 300 × 10–6 27. What is the expression for the crippling load for a
(b) 200 × 10–6 column of length l with one end fixed and other end
(c) 150 × 10–6 free?
(d) 100 × 10–6 2π2EI 2π2EI
20. A metal rod is rigidly fixed at its both ends. The (a) P= (b) P=
l2 4l2
temperature of the rod is increased by 100°C . If the
coefficient of linear expansion and elastic moduls of (c) P= 4π2EI (d) P= π2EI
the metal rod are 100 × 10–6/°C and 200 GPa l2 l2
Practice Work Book 5
28. Match List-I with List-II and select the correct answer 35. Which one of the following is the third basic
using the codes given below the Lists: component of robots besides power supply and
List-I List-II control (memory) console ?
(Theory of Failure (Predicted Ratio of (a) Software (b) Coaxial cable
Shear Stress to Direct (c) Mechanical unit arm (d) Microcomputer
Stress at Yield 36. Which of the following is a single point cutting
Condition for Steel tool?
Specimen (a) Hacksaw blade (b) Milling cutter
(c) Grinding wheel (d) Parting tool
A. Maximum shear 1. 1.0
37. Which one of the following values of index n is
stress theroy
associated with carbide tools when Taylor’s tool life
B. Maximum energy 2. 0.77
equation, VTn = constant is applied?
of distortion theory
(a) 0.1 to 0.15 (b) 0.2 to 0.4
C. Maximum principal 3. 0.62
(c) 0.45 to 0.6 (d) 0.65 to 0.9
strain theory
D. Maximum principal 4. 0.50 38. In the selection of optimal cutting conditions, the
strain theory requirement of surface finish would put a limit on
which of the following?
Codes:
(a) The maximum feed
A B C D
(b) The maximum depth of cut
(a) 1 2 4 3
(c) The maximum speed
(b) 4 3 1 2
(d) The maximum number of passes
(c) 1 3 4 2
(d) 4 2 1 3 39. During ultrasonic machining, the metal removal is
29. What is the strain energy stored in a body of volume achieved by:
V with stress a due to gradually applied load? (a) high frequency eddy currents
sE sE2 (b) high frequency sound waves
(a) (b) (c) hammering action of abrasive particles
V V
(d) rubbing action between tool and workpiece
sV2 s2V 40. Which of the following is an interference fit?
(c) (d)
E 2E (a) Push fit (b) Running fit
30. Gang milling is a: (c) Sliding fit (d) Shrink fit
(a) milling process for generating hexagonal sur- 41. The M and E-system in metrology are related to
faces measurement of:
(b) process of cutting gears (a) screw threads (b) flatness
(c) process in which two or more cutters are used (c) angularity (d) surface finish
simultaneously 42. Consider the following stetements:
(d) milling operation combined with turning 1. A large rake angle means lower strength of the
31. Which of the following cannot be cut by hobbing
cutting edge
process?
2. Cutting torque decreases with rake angle
(a) Helical gears (b) Bevel gears
Which of the statements given above is/are correct?
(c) Worm gears (d) Spur gears
(a) Only 1 (b) Only 2
32. It is required to cut screw threads with double start
(c) Both 1 and 2 (d) Neither 1 nor 2
and 2 mm pitch on a lathe having lead screw pitch of
43. Which one of the following is a qualitative technique
6 mm. What is the speed ratio between lathe spindle
of demand forecasting?
and lead screw?
(a) Correlation and regression analysis
(a) 1 : 3 (b) 3 : 1
(b) Moving average method
(c) 2 : 3 (d) 3 : 2
(c) Delphi technique
33. Which item best describes a CAM technology?
(d) Exponential smoothing
(a) Geometric modelling
(b) Documentation 44. Consider the following statements:
(c) Drafting 1. C functions can return arrays
(d) Numerical control 2. C functions can return functions
34. Flexible manufacturing allows for: 3. An array element can be void
(a) tool design and production 4. An array element can be a function
(b) automated design Which of the statements given above is/are correct?
(c) quick and inexpensive product (a) Only 1 and 4 (b) Only 1 and 3
(d) quality control (c) Only 2 (d) Only 3
6 Mechanical Engineering
45. Which one of the following statements is not correct Directions: The next questions consist of two
for the exponential smoothing method of demand statements: one labelled as the ‘Assertion (A)’ and the other
forecasting? as ‘Reason (R)’. You are to examine these two statements
(a) Demand for the most recent data is given more carefully and select the answers to these items using the
codes given below:
weightage
Codes:
(b) This method requires only the current demand an
(a) Both A and R are individually true and R is the
forecast demand
correct explanation of A
(c) This method assigns weight to all the previous
(b) Both A and R are individually true but R is not
data
the correct explanation of A
(d) This method gives equal weightage to all the (c) A is true but R is false
periods. (d) A is false but R is true
46. In an assembly line, when the workstation times are 49. Assertion (A) : Sampling plans with acceptance
unequal, the overall production rate of an assembly number greater than zero are generally better than
line is determined by the: sampling plans with acceptance number equal to
(a) fastest station time zero.
Reason (R) : Sampling plans with acceptance number
(b) slowest station time
greater than zero have a larger-sample size as
(c) average of all station times
compared to similar sampling plans with acceptance
(d) average of slowest and fastest station times
number equal to zero.
47. Match List-I with List-II and select the correct answer
50. Assertion (A) : Forging dies are provided with taper
using the codes given below the Lists:
or draft angles on vertical surfaces.
List-I List-II Reason (R) : It facilitates complete filling of die
(Parameter) (Definition) cavity and favourable grain flow.
51. Assertion (A) : In Addition Polymerization method,
A. Total work content 1. Aggregate of all the
polymer is produced by adding a second monomer to
work elements to be
the first, then a third monomer to this dimer and so
done on line
on.
B. Workstation process 2. Line inefficiency
Reason (R) : There must exist at least one double
which time results
bond in the monomer for Addition Polymerization
from the idle time
reaction.
due to imperfect
52. Assertion (A) :Concentric cylindrical helical springs
allocation of work
are used to have greater spring force in a limited
C. Cycle time among stations space.
3. Time interval Reason (R) : Concentric helical springs are wound
D. Balance delay between parts in opposite directions to prevent locking of coils under
coming off the line heavy dynamic loading.
4. Sum of the times of 53. Assertion (A) : In anti-friction hearings, the frictional
the work elements resistance is very low as the shaft held by it remains
done at a station in floating condition by the hydrodynamic pressure
developed by the lubricant.
Codes:
Reason (R) : In hydrodynamic journal bearings,
A B C D
hydrodynamic pressure is developed because of flow
(a) 1 4 3 2
of lubricant in a converging-diverging channel.
(b) 1 2 3 4 54. Assertion (A) : Crowning is provided on the surface
(c) 3 4 1 2 of a flat pulley to prevent slipping of the belt
(d) 3 2 1 4 sideways.
48. Which of the following are the advantages of Reason (R) : Belt creep, which is the reason for slip
subroutines in a program? of the belt sideways, is fully compensated by
1. They reduce execution time of the program providing crowning on the pulley.
55. Assertion (A) : Aluminium has poor weldability
2. They make the program more maintable
Reason (R) : Aluminium has high thermal conductivity
3. Modular development can be achieved
and high affinity to oxygen.
4. They can be parameterized.
56. Assertion (A) : In case of hot working of metals, the
Select the correct answer using the code given temperature at which the process is finally stopped
below should not be above the recrystallization temperature.
Codes: Reason (R) : If the process is stopped above the
(a) Only 2 and 3 (b) 1, 2, 3 and 4 recrystallization temperature, grain growth will take
(c) Only 2, 3 and 4 (d) Only 1 and 4 place again and spoil the attained structure.
Practice Work Book 7
57. What does hydrostatic pressure in extrusion process 62. Consider the following statements:
improve? The object of value analysis is
(a) Ductility 1. to reduce the cost
(b) Compressive strength 2. to increase the profit
(c) Brittleness 3. to improve quality
(d) Tensile strength
Which of the statements given above are correct?
58. Given :
(a) Only 1 and 2
J = 2, K = – 4, A = – 5, B = 0.4, C = 10.5
(b) Only 1 and 3
What are the values of the FORTRAN variables
(c) Only 2 and 3
JIP = J*K + J**K, IVAL = A + B + C?
(d) 1, 2 and 3
(a) 15.3 and 5.9, respectively
63. Consisder the following statements in respect of
(b) – 7.83 and 5.9, respectively
flexible couplings:
(c) – 7.83 and 5, respectively
(d) – 8 and 5, respectively 1. The flanges of flexible coupling are usually made
59. For taper turning on centre lathes, the method of of grey cast iron FG200.
swiveling the compound rest is preferred for: 2. In the analysis of flexible coupling, it is assumed
(a) long jobs with small taper angles that the power is transmitted by the shear
(b) long jobs with steep taper angles resistance of the pins.
(c) short jobs with small taper angles 3. Rubber bushes with brass lining are provided to
(d) short jobs with steep taper angles absorb misalignment between the two shafts.
60. Which of the following are the advantages of indirect
Which of the statements given above are correct?
addressing over direct addressing?
(a) 2 and 3
1. The program length is shorter
(b) Only 1 and 2
2. The program takes lesser time to execute
3. It allows the flexibility of using pointers (c) Only 2 and 3
4. It allows more efficient use of the cache (d) Only 1 and 3
Select the correct answer using the codes given below: 64. In case of belt drives, the effect of the centrifugal
Codes: tension is to:
(a) Only 1,2 and 3
(a) cause the belt to leave the pulley and increase the
(b) Only 1 and 3
power to be transmitted
(c) Only 2, 3 and 4
(b) cause the belt to stay on the pulley and increase
(d) Only 1 and 2
the power to be transmitted
61. Match the terms under the List-I with their description
(c) reduce the driving power of the belt
under the List-II in respect of computer organization
and select the correct answer using the code given (d) stretch the belt in longitudinal direction
under the Lists: 65. Which one of the following statements is not
List-I List-II correct?
(Term) (Description (a) Hooke’s joint is used to connect two rotating co-
planar, non-intersecting shafts
A. Distributed system 1. Multiple control units
2. Different steps of (b) Hooke’s joint is used to connect two rotating co-
B. MIMD instruction are planar, intersecting shafts
executed in separate (c) Oldham’s coupling is used to connect two parallel
stages with latches rotating shafts.
3. Independent (d) Hooke’s joint is used in the steering mechanism
C. SIMD processors which are for automobiles
networked together
66. Stresses in a screw thread are estimated by considering
D. Pipelined machine 4. Lock-step
the thread to be:
synchronization
(a) long cantilever beam projecting from the pitch
between multiple
cylinder
functional units
(b) long cantilever beam projecting from the root
Codes:
cylinder
A B C D
(a) 3 1 4 2 (c) short cantilever beam projecting from the root
(b) 4 2 3 1 cylinder
(c) 3 2 4 1 (d) short cantilever beam projecting from the pitch
(d) 4 1 3 2 cylinder