2015[2]
1. Which of the following statement apply to provision of flash gutter and flash land around the parts to be forged?
1. Small cavities are provided which are directly outside the die impression.
2. The volume of flash land and flash gutter should be about 20% – 25% of the volume of forging.
3. Gutter is provided to ensure complete closing of the die.
(a) 1 and 2 only
(b) 1 and 3 only
(c) 1, 2 and 3
(d) 2 and 3 only

Ans: c
2. A hole and a shaft have a basic size of 25 mm, and are to have a clearance fit with a maximum clearance of 0.02 mm and a minimum clearance of 0.01 mm. The hole tolerance is to be 1.5 times the shaft tolerance. The limits of both hole and shaft using hole basis system will be
(a) low limit of hole = 25mm, high limit of hole = 25.006 mm, upper limit of shaft = 24.99 mm and low limit of shaft = 24.986 mm
(b) low limit of hole = 25mm, high limit of hole = 25.026 mm, upper limit of shaft = 24.8 mm and low limit of shaft = 24.76 mm
(c) low limit of hole = 24 mm, high limit of hole = 25.006 mm, upper limit of shaft = 25mm and low limit of shaft = 24.99 mm
(d) low limit of hole = 25.006 mm, high limit of hole= 25 mm, upper limit of shaft =24.99 mm and low limit of shaft = 25mm.

Ans: a
3. Consider the following statements:
In case of assembly of mating part
1. the difference between hole size and shaft size is called allowance
2. in transition fit, small positive or negative clearance between shaft and hole member is employable
Which of the above statements is/are correct?
(a) 1 only
(b) Both 1 and 2
(c) 2 only
(d) Neither 1 nor 2

Ans: b
4. An organization has decided to produce a new product. Fixed cost for producing the product is estimated as Rs.1,00,000. Variable cost for producing the product is Rs.100. Market survey indicated that the product selling price could be Rs 200. The breakeven quantity is
(a) 1000
(b) 2000
(c) 500
(d) 900

Ans: a
5. Using exponential smoothing, a car manufacturing company predicted the demand for that year as 1040 cars. The actual sale was found to be 1140 cars. If the company’s forecast for the next year is 1080, what is the value of the smoothening constant?
(a) 0.4
(b) 0.6
(c) 0.7
(d) 1.2

Ans: a
6. Coarse feed, low rake angle, low cutting speed and insufficient cooling help produce
(a) continuous chips in ductile materials
(b) discontinuous chips in ductile materials
(c) continuous chips with builtup edges in ductile materials
(d) discontinuous chips in brittle materials

Ans: d
7. In NC machining, coordinated movement of separately driven axes motion is required to achieve the desired path of tool relative to workpiece. The generation of these reference signals is accomplished through a device called
(a) approximator
(b) interpolator
(c) coordinator
(d) director

Ans: b
8. A part is made from solid brass rod of 38 mm diameter and length 25 mm. The machining time taken to finish the part is 90 minutes and labour rate is Rs.2 per hour. Factory overheads are 50% of direct labour cost. The density of material is 8.6 gm per cubic cm and its cost is Rs1.625 per Newton. The factory cost of part will be
(a) Rs.8.40
(b) Rs.4.80
(c) Rs.14.80
(d) Rs.18.40

Ans: a
9. A company wants to expand the solid propellant manufacturing plant by the addition of more than 1 ton capacity curing furnace. Each ton of propellant must undergo 30 minutes of furnace time including loading and unloading operations. Furnace is used only 80 percent of the time due to power restrictions. The required output for the new layout is to be 16 tons per shift (8hours). Plant (system) efficiency is estimated at 50 percent of system capacity. The number of furnaces required will be
(a) 3
(b) 2
(c) 1
(d) 4

Ans: a
10. The purpose of providing side rake angle on the cutting tool is to
(a) avoid work from rubbing against tool
(b) control chip flow
(c) strengthen tool edge
(d) break chips

Ans: b
11. The annual demand of a commodity in a supermarket is 80000. The cost of placing an order is Rs 4,000 and the inventory cost of each item is Rs 40. What is the economic order quantity?
(a) 2000
(b) 4000
(c) 5656
(d) 6666

Ans: b
12.Consider the following statements:
In a singleserver queueing model
1. The arrivals is a memoryless process
2. The arrivals is described as a Poisson distribution
3. Uncertainty concerning the demand for service exists
Which of the above statements are correct?
(a) 1 and 2 only
(b) 1 and 3 only
(c) 1, 2 and 3
(d) 2 and 3 only

Ans: c
13. To construct an operating characteristic curve, an agreement has to be reached between producer and consumer through which of the following points?
1. Maximum proportion of defectives that will make the lot definitely unacceptable
2. The producer is willing to accept that some of satisfying the quality level (AQL) will be rejected (\alpha =5%)
3. Maximum level of percentage defectives that will make the lot definitely unacceptable
4. The consumer is willing to take lots of quality level (LTPD) even though they are unacceptable (\beta =10%),
(a) 1, 2 and 3 only
(b) 1, 2, 3 and 4
(c) 1, 2 and 4 only
(d) 2, 3 and 4 only

Ans: b
14. Assuming X and Y are the two control variables, the following are the constraints laid out for maximizing the profit:
Maximize profit (P) = 8X + 5Y
subject to
Constraint1: 2X + Y \le 1000
Constraint2 :3X + 4Y \le 2400
Constriant3:X + Y \le 800
Constraint4 :X – Y \le 350
Constraint5:X \ge 0
Constraint6 :Y \ge 0
Which of the above constraints is a redundant one and does not have any effect on the solution?
(a) Constraint1
(b) Constraint3
(c) Constraint4
(d) Constraint5 and Constraint6

Ans: b
15. A transportation problem consists of 3 sources and 5 destinations with appropriate rim conditions. The number of possible solutions is
(a) 15
(b) 225
(c) 6435
(d) 150

Ans: a
16. Maximize Z = 2X_{1 }+ 3X_{2}
subject to
2X_{1 }+ X_{2 }\le 6
X_{1 }– X_{2 }\ge 3
X_{1}, X_{2 }\ge 0
The solution to the above LPP is
(a) optimal
(b) infeasible
(c) unbounded
(d) degenerate

Ans: a
17. A company has a store which is manned by 1 attendant who can attend to 8 technicians in an hour. The technicians wait in the queue and they are attended on firstcomefirst served basis. The technicians arrive at the store on an average 6 per hour. Assuming the arrivals to follow Poisson and servicing to follow exponential distribution, what is the expected time spent by a technician in the system, what is the expected time spent by a technician in the queue and what is the expected number of technicians in the queue?
(a) 22.5 minutes, 30 minutes and 2.75 technicians
(b) 30 minutes, 22.5 minutes and 2.25 technicians
(c) 22.5 minutes, 22.5 minutes and 2.75 technicians
(d) 30 minutes, 30 minutes and 2.25 technicians

Ans: b
18. Objective function
Z = 5X_{1 }+ 4X_{2} (Maximize)
subject to
0\le X_{1}\le 12
0\le X_{2}\le 9
3X_{1 }+ 6X_{2}\le 66
X_{1}, X_{2 }\ge 0
What is the optimum value?
(a) 6, 9
(b) 12, 5
(c) 4, 10
(d) 0, 9

Ans: b
19. Which of the following defines the compiler’s function correctly?
(a) It translates highlevel language programs into object code
(b) It translates object code into a highlevel language
(c) It translates object code into assembly language instructions
(d) It translates assembly language instructions into object code

Ans: d
20. Which one of the following properties of work materials is responsible for the material removal rate in electrochemical machining?
(a) Hardness
(b) Atomic weight
(c) Thermal conductivity
(d) Ductility

Ans: b
21. In a crank and slotted lever type quick return mechanism, the link moves with an angular velocity of 20 rad/s, while the slider moves with the linear velocity of 1.5 m/s. The magnitude and direction of Coriolis component of acceleration with respect to angular velocity are
(a) 30 m/s^{2} and direction is such as to rotate slider velocity in the same sense as the angular velocity
(b) 30 m/s^{2} and direction is such as to rotate slider velocity in the opposite sense as the angular velocity
(c) 60 m/s^{2} and direction is such as to rotate slider velocity in the same sense as the angular velocity
(d) 60 m/s^{2} and direction is such as to rotate slider velocity in the opposite sense as the angular velocity.

Ans: c
22. Which of the following are associated with Ackerman steering mechanism used in automobiles?
1. Has both sliding and turning pairs
2. Less friction and hence long life
3. Mechanically correct in all positions
4. Mathematically not accurate except in three positions.
5. Has only turning pairs
6. Controls movement of two front wheels
(a) 2, 4, 5 and 6
(b) 1, 2, 3 and 6
(c) 2, 3, 5 and 6
(d) 1, 2, 3 and 5

Ans: a
23. The displacement of a follower of a cam in a printing machine is represented by the expression
x={ 10\theta }+120{ \theta }^{ 2 }+1500{ \theta }^{ 3 }+2000{ \theta }^{ 4 }+2500{ \theta }^{ 5 }
where \theta is the angle of rotation of the cam. The jerk given by the system at any position is
(a) { 9000\omega }^{ 3 }+48000{ \omega }^{ 3 }\theta +150000{ \omega }^{ 3 }{ \theta }^{ 2 }
(b) { 9000\omega }^{ 3 }
(c) { 240\omega }^{ 2 }+9000{ \omega }^{ 2 }\theta +24000{ \omega }^{ 2 }{ \theta }^{ 2 }+5000{ \omega }^{ 3 }{ \theta }^{ 3 }
(d) 48000{ \omega }^{ 3 }\theta +150000{ \omega }^{ 3 }{ \theta }^{ 2 }

Ans: a
24. A body starting from rest moves in a straight line with its equation of motion being, s = 2t^{3} – 3t^{2} + 2t + 1. where s is displacement in m and t is time in s. Its acceleration after one second is
(a) 6 m/s^{2}
(b) 2 m/s^{2}
(c) 12 m/s^{2}
(d) 3 m/s^{2}

Ans: a
25. The crankshaft of reciprocating engine having a 20 cm crank and 100 cm connecting rod rotates at 210 r.p.m. When the crank angle is 45^{0}, the velocity of piston is nearly
(a) 1.8 m/s
(b) 1.9 m/s
(c) 18 m/s
(d) 19 m/s

Ans: 3.5
26. While designing a cam, pressure angle is one of the most important parameters which is directly proportional to
(a) pitch circle diameter
(b) prime circle diameter
(c) lift of cam
(d) base circle diameter

Ans: d
27. A fourbar mechanism is as shown in the figure below. At the instant shown, AB is shorter than CD by 30 cm. AB is rotating at 5 rad/s and CD is rotating at 2 rad/s:
The length of AB is
(a) 10 cm
(b) 20 cm
(c) 30 cm
(d) 40 cm

Ans: b
28. A governor is said to be isochronous when the equilibrium speed is
(a) variable for different radii of rotation of governor balls
(b) constant for all radii of rotation of the balls within the working range
(c) constant for particular radii of rotation of governor balls
(d) constant for only one radius of rotation of governor balls

Ans: b
29. A planetary gear train is gear train having
(a) a relative motion of axes and the axis of at least one of the gears also moves relative to the frame
(b) no relative motion of axes and no relative motion of axes with respect to the frame
(c) no relative motion of axes and the axis of at least one of the gears also moves relative to the frame
(d) a relative motion of axes and none of the axes of gears has relative motion with the frame

Ans: a
30. The flywheel of a machine having weight of 4500 N and radius of gyration of 2 m has cyclic fluctuation of speed from 125 r.p.m to 120 r.p.m. Assuming g = 10 m/s^{2} , the maximum fluctuation of energy is
(a) 12822 Nm
(b) 24200 Nm
(c) 14822 Nm
(d) 12100 Nm

Ans: d
31. Alumina doped with magnesia will have reduced thermal conductivity because its structure becomes
(a) amorphous
(b) free of pores
(c) crystalline
(d) mixture of crystalline and glass

Ans: a
32. Which of the following statements are associated with complete dynamic balancing of rotating systems?
1. Resultant couple due to all inertia forces is zero.
2. Support reactions due to forces are zero but not due to couples.
3. The system is automatically statically balanced.
4. Centre of masses of the system lies on the axis of rotation.
(a) 1, 2, 3 and 4
(b) 1, 2, and 3 only
(c) 2, 3 and 4 only
(d) 1, 3 and 4 only

Ans: d
33. Which of the following statements is correct about the balancing of a mechanical system?
(a) If it is under static balance, then there will be dynamic balance also
(b) If it is under dynamic balance, then there will be static balance also
(c) Both static as well as dynamic balance have to be achieved separately
(d) None of the above

Ans: c
34. The accelerometer is used as a transducer to measure earthquake in Richter scale. Its design is based on the principle that
(a) its natural frequency is very low in comparison to the frequency of vibration
(b) its natural frequency is very high in comparison to the frequency of vibration
(c) its natural frequency is equal to the frequency of vibration
(d) measurement of vibratory motion is without any reference point

Ans: c
35. As compared to the time period of a simple pendulum of the earth, its time period on the moon will be
(a) 6 times higher
(b) 6 times lower
(c) \sqrt { 6 } times higher
(d) \sqrt { 6 } times lower

Ans: c
36. While calculating the natural frequency of a springmass system, the effect of the mass of the spring is accounted for by adding X times its value to the mass, where X is
(a) \frac { 1 }{ 2 }
(b) \frac { 1 }{ 3 }
(c) \frac { 1 }{ 4 }
(d) \frac { 3 }{ 4 }

Ans: b
37. A block of mass 10 kg is placed at the free end of a cantilever beam of length 1 m and second moment of area 300 mm^{4} .Taking Young’s modulus of the beam material as 200 GPa, the natural frequency of the system is
(a) 30\sqrt { 2 } rad/s
(b) 2\sqrt { 3 } rad/s
(c) 3\sqrt { 2 } rad/s
(d) 20\sqrt { 3 } rad/s

Ans: c
38. The speed rating for turbine rotors is invariably more than \sqrt { 2 } times its natural frequency to
(a) increase stability under heavy load and high speed
(b) isolate vibration of the system from the surrounding
(c) minimize deflection under dynamic loading as well as to reduce transmissibility of force to the surrounding
(d) None of the above

Ans: b
39. The magnitude of swaying couple due to partial balance of the primary unbalancing force in locomotive is
(a) inversely proportional to the reciprocating mass
(b) directly proportional to the square of the distance between the centre lines of the two cylinders
(c) inversely proportional to the distance between the centerlines of the two cylinders
(d) directly proportional to the distance between the centerlines of the two cylinders

Ans: d
40. The power of a governor is the work done at
(a) the governor balls for change of speed
(b) the sleeve for zero change of speed
(c) the sleeve for a given rate of change of speed
(d) each governor ball for given percentage change of speed

Ans: c
41. Copper has FCC structure; its atomic radius is 1.28A and atomic mass is 63.5. The density of copper will be
(a) 8.9\times { 10 }^{ 3 }kg/{ mm }^{ 3 }
(b) 8.9\times { 10 }^{ 3 }kg/{ m }^{ 3 }
(c) 8.9\times { 10 }^{ 3 }g/{ m }^{ 3 }
(d) 8.9\times { 10 }^{ 3 }g/{ mm }^{ 3 }

Ans: b
42. A plane intersects the coordinate axes at x=\frac { 2 }{ 3 } ,y=\frac { 1 }{ 3 } and z=\frac { 1 }{ 2 } . What is the Miller index of this plane?
(a) 932
(b) 432
(c) 423
(d) 364

Ans: d
43. What is the diameter of the largest sphere is terms of lattice parameter a, which will fit the void at the centre of the cube edge of a BCC crystals?
(a) 0.134a
(b) 0.25a
(c) 0.433a
(d) 0.5a

Ans: c
44. If the atomic radius of aluminum is r, what is its unit cell volume?
(a) { \left( \frac { 2r }{ \sqrt { 2 } } \right) }^{ 3 }
(b) { \left( \frac { 4r }{ \sqrt { 2 } } \right) }^{ 3 }
(c) { \left( \frac { 2r }{ \sqrt { 3 } } \right) }^{ 3 }
(d) { \left( \frac { 4r }{ \sqrt { 3 } } \right) }^{ 3 }

Ans: b
45. Consider the following statements regarding the behavior of dislocations:
1. Only edge dislocation and mixed dislocation can have glide motion.
2. A screw dislocation cannot have glide motion.
3. Dislocation moves in the direction perpendicular to that of shear stress.
4. Motion of dislocation occurs on slip plane that contains Burger’s vector and direction vector.
Which of the above statements are correct?
(a) 1, 2 and 3 only
(b) 1, 2 and 4 only
(c) 2, 3 and 4 only
(d) 1, 2, 3 and 4

Ans: b
46. A binary alloy of Cu and Ni containing 20 wt% Ni at a particular temperature coexists with solid phase of 26 wt% Ni and liquid phase of 16 wt% Ni. What is the weight ratio of solid phase and liquid phase?
(a) 1:1
(b) 3:2
(c) 2:3
(d) 1:2

Ans: b
47. Elements A and B form eutectic type binary phase diagram and the eutectic composition is 60 wt% B. If just below eutectic temperature, the eutectic phase contains equal amounts (by wt) of two solid phases, then the compositions of the two solid phases are
(a) 20 wt% B and 90 wt% B
(b) 30 wt% B and 90 wt% B
(c) 20 wt% B and 80 wt% B
(d) 30 wt% B and 80 wt% B

Ans: d
48. Consider the following statements:
In a binary phase diagram
1. the freezing point of the alloy is minimum.
2. eutectic mixture solidifies at a constant temperature like pure metal
3. eutectic reaction is irreversible
4. at eutectic temperature, liquid of two metals will change into two solids
Which of the above statements are correct?
(a) 1, 2 and 3 only
(b) 1, 3 and 4 only
(c) 1, 2 and 4 only
(d) 1, 2, 3 and 4

Ans: c
49. At room temperature, \alpha – iron contains negligible amount of carbon, cementite contains 6.67 % C and pearlite contains 0.8% C. Pearlite contains how much cementite?
(a) 8%
(b) 10%
(c) 12%
(d) 14%

Ans: c
50. Two metals A and B are completely immiscible in solid and liquid state. Melting point of A is 800^{0}C and melting point of B is 600^{0}C. They form eutectic at 200^{0}C with 40% B and 60% A. The 50% B alloy contains
(a) 83.33% B and 1.67% of eutectic
(b) 83.33% of eutectic and 16.67% B
(c) 50% B and 50% of eutectic
(d) 40% B and 60% of eutectic

Ans: b
51. What is the interplanar spacing between (200), (220), (111) planes in an FCC crystal of atomic radius 1.246A?
(a) d_{(200)}=1.762A^{0}, d_{(220)}=1.24A^{0}, d_{(111)}=2.034A^{0}
(b) d_{(200)}=1.24A^{0}, d_{(220)}=1.762A^{0}, d_{(111)}=2.034A^{0}
(c) d_{(200)}=2.034A^{0}, d_{(220)}=1.24A^{0}, d_{(111)}=1.762A^{0}
(d) d_{(200)}=2.5A^{0}, d_{(220)}=4.2A^{0}, d_{(111)}=2.6A^{0}

Ans: c
52. Rotary swaging is process for shaping
(a) round bars and tubes
(b) billets
(c) dies
(d) rectangular blocks

Ans: a
53. Consider the following statements:
In shell moulding
1. a single parting plane should be provided for mould
2. detachable patterns parts and cores could be included
3. minimum rounding radii of 2.5 mm to 3 mm should be used
4. draft angles of not less than 1^{0} should be used
Which of the above statements are correct?
(a) 1, 3 and 4 only
(b) 1, 2 and 3 only
(c) 2, 3 and 4 only
(d) 1, 2, 3 and 4

Ans: d
54. A big casting is to have hole, to be produced by using a core of 10 cm diameter and 200 cm long. The density { \rho }_{ metal } is 0.077 N/cm^{3} and density { \rho }_{ core } is 0.0165 N/cm^{3}. What is the upward force acting on the core prints?
(a) 200.5 N
(b) 1100.62 N
(c) 950.32 N
(d) 350.32 N

Ans: c
55. Consider the following:
The purpose of lapping process is
1. to produce geometrically true surface
2. to correct minor surface imperfections
3. to improve dimensional accuracy
4. to provide very close fit between the constant surfaces
Which of the above are correct?
(a) 1, 2 and 3 only
(b) 1, 3 and 4 only
(c) 2, 3 and 4 only
(d) 1, 2, 3 and 4

Ans: d
56. Centre lathe is to be used to cut inch thread of 4 threads per inch. Lead screw of lathe has 3 mm pitch. Then change gear to be used is
(a) \frac { 1 }{ 12 }
(b) \frac { 127 }{ 60 }
(c) \frac { 30 }{ 127 }
(d) \frac { 20 }{ 80 }

Ans: b
57. Consider the following statements in respect of the oxidizing flame due to excess of oxygen in welding:
1. At high temperature, it combines with many metals to form hard and brittle oxides.
2. It causes the weld bead and the surrounding area to have a scummy appearance.
3. It has good welding effect in welding of copperbase metal.
Which of the above statements are correct?
(a) 1, 2 and 3
(b) 1 and 2 only
(c) 1 and 3 only
(d) 2 and 3 only

Ans: a
58. A cutter tip is initially at X = 10 mm, Y = 10 mm. In a rapid motion, using G00 code, it moves to X = 160 mm, Y=120 mm. The X and Y axes have maximum speed of 10000 mm/min and 5000 mm/min respectively. Operating at maximum speed, what is the time it will take to reach the destination?
(a) 0.90s
(b) 1.08s
(c) 1.20 s
(d) 2.16s

Ans: b
59. If n=0.5 and C=300 for the cutting speed and the tool life relation, when cutting speed is reduced by 25%, the tool life will be increased by
(a) 100%
(b) 95%
(c) 78%
(d) 50%

Ans: c
60. Which of the following statements are correct for temperature rise in metal cutting operation?
1. It adversely affects the properties of tool material.
2. It provides better accuracy during machining.
3. It causes dimensional changes in workpiece and affects accuracy of machining.
4. It can distort the accuracy of machine tool itself.
(a) 1 and 2
(b) 2 and 3
(c) 3 and 4 only
(d) 1, 3 and 4

Ans: d
61. Consider the following:
The parallel fillet welded joint is designed for
1. tensile strength
2. compressive strength
3. bending strength
4. shear strength
Which of the above is/are correct?
(a) 4 only
(b) 3 only
(c) 2 and 3
(d) 1 and 4

Ans: a
62. If the permissible crushing stress for the material of a key is double the permissible shear stress, then the sunk key will be equally strong in shearing and crushing if the key is a
(a) rectangular key with width equal to half the thickness
(b) rectangular key with width equal to twice the thickness
(c) square key
(d) rectangular key with width equal to onefourth the thickness

Ans: c
63. Very small quantity of carbon in iron as in steels forms interstitial solid solution mainly because atomic size(s) of
(a) carbon and iron are almost same
(b) iron is very much smaller than that of carbon
(c) carbon is very much smaller than that of iron
(d) None of the above

Ans: c
64. In a cotter joint, the width of the cotter at the centre is 5 cm, while its thickness is 1.2 cm. The load acting on the cotter is 60 kN. The shear stress developed in the cotter is
(a) 50 N/mm^{2}
(b) 100 N/mm^{2}
(c) 120 N/mm^{2}
(d) 200 N/mm^{2}

Ans: a
65. The use of straight or curved external gear teeth in mesh with internal teeth in ‘gear and spline couplings’ is specifically employed accommodate
(a) torsional misalignment
(b) parallel misalignment
(c) angular misalignment
(d) substantial axial movements between shafts

Ans: c
66. For a power screw having square threads with lead angle of 45^{0} and coefficient of friction of 0.15 between screw and nut, the efficiency of the power screw, neglecting collar friction, is given by
(a) 74%
(b) 64%
(c) 54%
(d) 44%

Ans: a
67. Aquaplaning occurs in vehicle tyres when there is continuous film of fluid between the tyre and the wet road. It leads to
(a) oscillatory motion of the vehicle
(b) jamming the brake of the vehicle
(c) jamming the steering mechanism of the vehicle
(d) loss of control of the vehicle

Ans: d
68. If the angle of wrap on smaller pulley of diameter 250 mm is 120^{0} and diameter of larger pulley is twice the diameter of smaller pulley, then the centre distance between the pulleys for an open belt drive is
(a) 1000 mm
(b) 750 mm
(c) 500 mm
(d) 250 mm

Ans: d
69. If the velocity ratio for an open belt drive is 8 and the speed of driving pulley is 800 r.p.m, then considering an elastic creep of 2% the speed of the driven pulley is
(a) 104.04 r.p.m
(b) 102.04 r.p.m
(c) 100.04 r.p.m
(d) 98.04 r.p.m

Ans: d
70. Two shafts A and B are of same material, and A is twice the diameter of B. The torque that can be transmitted by A is
(a) 2 times that of B
(b) 8 times that of B
(c) 4 times that of B
(d) 6 times that of B

Ans: b
71. A worm gear set is designed to have pressure angle of 30^{0} which is equal to the helix angle. The efficiency of the worm gear set at an interface friction of 0.05 is
(a) 87.9%
(b) 77.9%
(c) 67.9%
(d) 57.9%

Ans: a
72. Consider the following statements:
The axes of spiral bevel gear are nonparallel and intersecting.
1. The most common pressure angle for spiral bevel gear is 20^{0}.
2. The most common spiral angle for spiral bevel gear is 35^{0}.
3. Spiral bevel gears are generally interchangeable.
4. Spirals are noisy and recommended for low speeds of 10 m/s.
Which of the above statements are correct?
(a) 1 and 4
(b) 1 and 2
(c) 2 and 3
(d) 3 and 4

Ans: a
73. Consider the following statements:
In case of helical gears, teeth are cut at an angle to the axis of rotation of the gears.
1. Helix angle introduces another ratio called axial contact ratio.
2. Transverse contact ratio is equal to axial contact ratio in helical gears.
3. Large transverse contact ratio does not allow multiple teeth to share the load.
4. Large axial contact ratio will cause larger axial force component.
Which of the above statements are correct?
(a) 1 and 2
(b) 2 and 3
(c) 1 and 4
(d) 3 and 4

Ans: c
74. In an interference fit between a shaft and a hub, the state of stress in the shaft due to interference fit is
(a) only compressive radial stress
(b) a tensile radial stress and a compressive tangential stress
(c) a tensile tangential stress and a compressive radial stress
(d) a compressive tangential stress and a compressive radial stress

Ans: d
75. In case the number of teeth on two bevel gears in mesh is 30 and 60 respectively, then the pitch cone angle of the gear will be
(a) tan^{1} 2
(b) \frac { \pi }{ 2 } + tan^{1} 2
(c) \frac { \pi }{ 2 } – tan^{1} 0.5
(d) tan^{1} 0.5

Ans: d
76. In skew bevel gears, the axes are
(a) nonparallel and nonintersecting, and teeth are curved
(b) nonparallel and nonintersecting, and teeth are straight
(c) intersecting, and teeth are curved and oblique
(d) intersecting, and teeth are curved and can be ground

Ans: a
77. Consider that modern machines mostly use short bearings due to the following reasons:
1. l/d of the most modern bearings is in the range of 1/4 to 2
2. No end leakage of oil from the bearing
3. Shaft deflection and misalignment do not affect the operation.
4. Can be applied to both hydrodynamic and hydrostatic cases
Which of the above are correct?
(a) 1 and 4
(b) 2 and 3
(c) 1 and 3
(d) 2 and 4

Ans: c
78. Consider the following statements in connection with thrust bearings:
1. Cylindrical thrust bearings have higher coefficient of friction than ball thrust bearings.
2. Taper rollers cannot be employed for thrust bearings.
3. Doublerow thrust ball bearings is not possible.
4. Lower race, outer race and retainer are readily separable in thrust bearings.
Which of the above statements are correct?
(a) 1 and 2
(b) 2 and 3
(c) 3 and 4
(d) 1 and 4

Ans: d
79. The behavior of metals in which strength of a metal is increased and the ductility is decreased on heating at a relatively low temperature after cold working is known as
(a) clustering
(b) strain aging
(c) twinning
(d) screw dislocation

Ans: b
80. If the equivalent load in case of a radial ball bearing is 500 N and the basic dynamic load rating is 62500 N, then L_{10} life of this bearing is
(a) 1.953 million of revolutions
(b) 3.765 million of revolutions
(c) 6.953 million of revolutions
(d) 9.765 million of revolutions

Ans: a
81. Statement (I): The cam in contact with a follower is a case of complete constraint.
Statement (II): The pair, cam and follower, by itself does not guarantee continuity of contact all the time.

Ans: c
82. Statement (I): Involute pinions can have any number of teeth.
Statement (II): Involute profiles in mesh satisfy the constant velocity ratio condition.

Ans: d
83. Statement (I): Hooke’s joint connects two nonparallel nonintersecting shafts to transmit motion with a constant velocity ratio.
Statement (II): Hooke’s joint connects two shafts the axes of which do not remain in alignment while in motion.

Ans: d
84. Statement (I): Lewis equation for design of involute gear tooth predicts the static load capacity of a cantilever beam of uniform strength.
Statement (II): For a pair of gears in mesh, pressure angle and module must be same to satisfy the condition of interchangeability and correct gearing.

Ans: b
85. Statement (I): Tensile strength of CI is much higher than that of MS.
Statement (II): Percentage of carbon in CI is more than 1.5.

Ans: d
86. Statement (I): Centrifugal clutches are designed to provide automatic and smooth engagement of load to driving member.
Statement (II): Since the operating centrifugal force is a function of square of angular velocity, the friction torque for accelerating a load is also a function of square of speed driving member.

Ans: a
87. Statement (I): Heating the steel specimen in the furnace up to austenitize temperature followed by furnace cooling is termed annealing.
Statement (II): Annealed steel specimen possesses fine pearlitic structure.

Ans: b
88. Statement (I): The susceptibility of a ferromagnetic material decreases with an increase in Curie temperature.
Statement (II): A critical temperature at which the alignment of magnetic moments vanishes is called Curie temperature.

Ans: c
89. Statement (I): Fiberglass is polymer composite made of a plastic matrix containing fine fibers of glass.
Statement (II): Fiberglass acquires strength from the polymer and flexibility from the glass.

Ans: c
90. Statement (I): Industrial rotors will not have uniform diameter throughout their lengths.
Statement (II): These rotors will have to accommodate transmission elements like pulleys and gears and supports like antifriction bearings.

Ans: a
91. Statement (I): Cored induction furnace cannot be used for intermittent operation.
Statement (II): Cored induction furnace, through most efficient, requires a liquid metal charge while starting.

Ans: a
92. Statement (I): Lowcarbon steel has high weldability and is more easily welded.
Statement (II): Higher carbon contents tend to soften the welded joints resulting in development of cracks.

Ans: a
93. Statement (I): For cutting multistart threads, the speed ratio is expressed in terms of the lead of the job thread and lead of the lead screw threads.
Statement (II): The speed of the job is reduced to one third or onefourth of the job speed used in the turning operation.

Ans: b
94. Statement (I): The Bauschinger effect is observed in tension test of mild steel specimen due to loss of mechanical energy during local yielding.
Statement (II): The Bauschinger effect is a function of section modulus of specimen under test.

Ans: c
95. Statement (I): The ceramic tools used in machining of material have highly brittle tool tips.
Statement (II): Ceramic tools can be used on hardtomachine work material.

Ans: b
96. Statement (I): In chain drives, angle of articulation through which link rotates during engagement and disengagement, is greater for a small number of teeth.
Statement (II): The greater angle of articulation will increase the life of the chain.

Ans: c
97. Statement (I): The CNC is an NC system utilizing a dedicated stored program to perform all numerical control functions in manufacturing.
Statement (II): The DNC is a manufacturing process in which a number of process machines are controlled by a computer through direct connection and real time analysis.

Ans: b
98. Statement (I): In interference fit, the outer diameter of the shaft is greater than the inner diameter of the hole.
Statement (II): The amount of clearance obtained from the assembly of hole and shaft resulting in interference fit is called positive clearance.

Ans: c
99. Statement (I): One of the most commonly used techniques for testing surface integrity of material is metallography.
Statement (II): Surface integrity of material does not contribute for the mechanical and metallurgical properties.

Ans: c
100. Statement (I): The change in critical path requires rescheduling in a PERT network.
Statement (II): Some of the activities cannot be completed in time due to unexpected breakdown of equipment or nonavailability of raw materials.

Ans: b
101. A copper rod of 2 cm diameter is completely encased in a steel tube of inner diameter 2 cm and outer diameter 4 cm. Under an axial load, the stress in the steel tube is 100 N/mm^{2}. If E_{s} = 2E_{c}, then the stress in the copper rod is
(a) 50 N/mm^{2}
(b) 33.33 N/mm^{2}
(c) 100 N/mm^{2}
(d) 300 N/mm^{2}

Ans: a
102. A system under biaxial loading induces principal stresses of 100 N/cm^{2} tensile and 50 N/cm^{2} compressive at a point. The normal stress at that point on the maximum shear stress plane is
(a) 75 N/cm^{2} tensile
(b) 50 N/cm^{2} compressive
(c) 100 N/cm^{2} tensile
(d) 25 N/cm^{2} tensile

Ans: d
103. In a biaxial state of stress, normal stresses are { \sigma }_{ x }= 900 N/mm^{2}, { \sigma }_{ y } = 100 N/mm^{2} and shear stress \tau = 300 N/mm^{2}. The maximum principal stress is
(a) 800 N/mm^{2}
(b) 900 N/mm^{2}
(c) 1000 N/mm^{2}
(d) 1200 N/mm^{2}

Ans: c
104. A constitutional diagram shows relationship among which of the following combinations in a particular alloy system?
(a) Temperature and composition
(b) Temperature and phases present
(c) Temperature, composition and phase present
(d) Temperature and pressure

Ans: c
105. The state of stress at a point in a body is given by { \sigma }_{ x } = 100 MPa and { \sigma }_{ y } = 200 MPa. One of the principal stresses { \sigma }_{ 1 } = 250 MPa. The magnitudes of the other principal stress and the shearing stresses { \tau }_{ xy } are respectively
(a) 50\sqrt { 3 } MPa and 50 MPa
(b) 100 MPa and 50\sqrt { 3 } MPa
(c) 50 MPa and 50\sqrt { 3 } MPa
(d) 50\sqrt { 3 } MPa and 100 MPa

Ans: c
106. Consider the following statements regarding powder metallurgy:
1. Refractory materials made of tungsten can be manufactured easily.
2. In metal powder, control of grain size results in relatively much uniform structure.
3. The powder heated in die or mould at high temperature is then pressed and compacted to get desired shape and strength.
4. In sintering, the metal powder is gradually heated resulting in coherent bond.
Which of the above statements are correct?
(a) 1, 2 and 3 only
(b) 1, 2 and 4 only
(c) 2, 3 and 4 only
(d) 1, 2, 3 and 4

Ans: d
107. The magnitudes of principal stresses at a point are 250 MPa tensile and 150 MPa compressive. The magnitudes of the shearing stress on a plane on which the normal stress is 200 MPa tensile and the normal stress on a plane at right angle to this plane are
(a) 50\sqrt { 7 } MPa and 100 MPa (tensile)
(b) 100 MPa and 100 MPa (compressive)
(c) 50\sqrt { 7 } MPa and 100 MPa (compressive)
(d) 100 MPa and 50\sqrt { 7 } MPa (tensile)

Ans: c
108. The state of stress at a point is given by { \sigma }_{ x } = 100MPa, { \sigma }_{ y } = 50MPa and { \tau }_{ xy } = 100MPa. The centre of Mohr’s circle and its radius will be
(a) \left( { \sigma }_{ x }=75MPa, { \tau }_{ xy }=0 \right) and 75 MPa
(b) \left( { \sigma }_{ x }=25MPa, { \tau }_{ xy }=0 \right) and 125 MPa
(c) \left( { \sigma }_{ x }=25MPa, { \tau }_{ xy }=0 \right) and 150 MPa
(d) \left( { \sigma }_{ x }=75MPa, { \tau }_{ xy }=0 \right) and 125 MPa

Ans: b
109. Consider the following statements related to Mohr’s circle for stresses in case of plane stress:
1. The construction is for variations of stress in a body.
2. The radius of the circle represents the magnitude of the maximum shearing stress.
3. The diameter represents the difference between the two principal stresses.
Which of the above statement are correct?
(a) 1, 2 and 3
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1 and 2 only

Ans: b
110. The figure shows a steel piece of diameter 20 mm at A and C and 10 mm at B. The lengths of three sections A, B and C are each equal to 20 mm. The piece is held between two rigid surfaces X and Y. The coefficient of linear expansion \alpha =1.2\times { 10 }^{ 5 }{ / }^{ 0 }C and Young’s modulus E=2\times { 10 }^{ 5 }MPa for steel:
When the temperature of this piece increases by 50^{0}C, the stresses in sections A and B are
(a) 120 MPa and 480 MPa
(b) 60 MPa and 240 MPa
(c) 120 MPa and 120 MPa
(d) 60 MPa and 120 MPa

Ans: b
111. For a material following Hooke’s law, the values of elastic and shear moduli are 3\times { 10 }^{ 5 }MPa and 1.2\times { 10 }^{ 5 }MPa respectively. The value for bulk modulus is
(a) 1.5\times { 10 }^{ 5 }MPa
(b) 2\times { 10 }^{ 5 }MPa
(c) 2.5\times { 10 }^{ 5 }MPa
(d) 3\times { 10 }^{ 5 }MPa

Ans: b
112. At a point in a body, { \epsilon }_{ 1 }=0.0004 and { \epsilon }_{ 2 }=0.00012. If E=2\times { 10 }^{ 5 } MPa and \mu =0.3, the smallest normal stress and the largest shearing stress are
(a) 40 MPa and 40 MPa
(b) 0 MPa and 40 MPa
(c) 80 MPa and 0 MPa
(d) 0 MPa and 80 MPa

Ans: b
113. A cantilever of length 1.2 m carries a concentrated load of 12 kN at the free end. The beam is of rectangular crosssection with breadth equal to half the depth. The maximum stress due to bending is not to exceed 100 N/mm^{2}. The minimum depth of the beam should be
(a) 120 mm
(b) 60 mm
(c) 75 mm
(d) 240 mm

Ans: a
114. Two strain gauges fixed along the principal directions on a plane surface of a steel member recorded strain values of 0.0013 tensile and 0.0013 compressive respectively. Given that the value of E=2\times { 10 }^{ 5 }MPa and \mu =0.3, the largest normal and shearing stress at this point are
(a) 200 MPa and 200 MPa
(b) 400 MPa and 200 MPa
(c) 260 MPa and 260 MPa
(d) 260 MPa and 520 MPa

Ans: a
115. A beam ABCD, 6 m long, is supported at B and C, 3 m apart with overhangs AB = 2m and CD = 1 m. It carries a uniformly distributed load of 100 kN/m over its entire length:
The maximum magnitudes of bending moment and shear forces are
(a) 200 kNm and 250 kN
(b) 200 kNm and 200 kN
(c) 50 kNm and 200 kN
(d) 50 kNm and 250 kN

Ans: b
116. A solid circular crosssection cantilever beam of diameter \phi = 100 mm carries a shear force of 10 kN at the free end. The maximum shear stress is
(a) \frac { 4 }{ 3\pi } Pa
(b) \frac { 3\pi }{ 4 } Pa
(c) \frac { 3\pi }{ 16 } Pa
(d) \frac { 16 }{ 3\pi } Pa

Ans: d
117. A beam of length L simply supported at its ends carrying a total load W uniformly distributed over its entire length deflects at the centre by \delta and has a maximum bending stress \sigma . If the load is substituted by a concentrated load W_{1} at midspan such that the deflection at the centre remains unchanged, the magnitude of the load W_{1} and the maximum bending stress will be
(a) 0.3W and 0.3\sigma
(b) 0.6W and 0.6\sigma
(c) 0.3W and 0.6\sigma
(d) 0.6W and 0.3\sigma

Ans: d
118. For a rectangular section beam, if the beam depth is doubled, keeping the width, length and loading same, the bending stress is deceased by a factor
(a) 2
(b) 4
(c) 6
(d) 8

Ans: b
119. A helical compression spring of stiffness K is cut into two pieces, each having equal number of turns and kept sidebyside under compression. The equivalent spring stiffness of this new arrangement is equal to
(a) 4K
(b) 2K
(c) K
(d) 0.5 K

Ans: a
120. A beam AB simply supported at its ends A and B, 3 m long, carries a uniformly distributed load of 1 kN/m over its entire length and concentrated load of 3 kN, at 1 m from A:
If ISJB 150 with I_{xx} = 300 cm^{4 }is used for the beam, the maximum value of bending stress is
(a) 75 MPa
(b) 85 MPa
(c) 125 MPa
(d) 250 MPa

Ans: a