GATE Mechanical Engineering questions:

Q.1 — Q.20 Carry One Mark Each.

1. Match the items in columns I and II.

(A) P - 1 Q - 4 R - 3 S - 2

(B) P - 1 Q - 4 R - 2 S - 3

(C) P - 1 Q - 3 R - 2 S - 4

(D) P - 4 Q - 1 R - 2 S – 3

2. The solution of the differential equation

+2xy=e with y(O)=lis:

dx ‘.7 1-

(A) (1+x)e

(B) (1+x)e

(C) (1_x)e

(D) (1_x)e

3. Let x denote a real number. Find out the INCORRECT statement.

(A) S = {x: x > 3} represents the set of all real numbers greater than 3

(B) S = {x: x2 <01 represents the empty set

(C) S = {x : x A and x B} represents the union of set A and set B

(D) 5 = {x: a < x < b} represents the set of all real numbers between a and b, where a and b

are real numbers.

4. For a four-bar linkage in togQle position, the value of mechanical advantage is:

(A) 0.0 ‘-:7

(B) 0.5

(C) 1.0

(D)

5. The differential equation governing the vibrating system is:

(A) mii-t-ck+k(x-y)=0

(B) m(ii—’)+c(x—’)+kx=0

(C) mi+c(x-y)+kx=0

(D) m(i—y)+c(x—j’)+k(x—y)=O

6. A pin-ended column of length L, modulus of elasticity E and second moment of the crosssectionalarea I is loaded centrically by a compressive load P. the critical buckling load (Pcr) isgiven by

(A) Pcr22

(B)

(C)

(D) ‘°crL2

7. The number of inversions for a slider crank mechanism is:

(A) 6

(B) 5

(C) 4 ‘-1 - I

(D) 3

8. For a Newtonian fluid

(A) shear stress is proportional to shear strain

(B) rate of shear stress is proportional to shear strain

(C) shear stress is proportional to rate of shear strain

(D) rate of shear stress is proportional to rate of shear strain

9. In a two-dimensional velocity field with velocities u and valong the x and y directions

respectively, the convective acceleration along the x-direction is given by

3u 3u

(A) u—+v—

3x 3y

3u v

(B) u—+v—

3v 3u

(C) u—+v-—

3x 3y

3u 3u

(D) v—+u—

Jx Jy

10. Dew point temperature is the temperature at which condensation begins when

the air is cooled at constant.

(A) volume

(B) entropy

(C) pressure

(D) enthalpy

11. In a composite slab, the temperature at the interface (7nter)bet9 two materials is equal to

the average of the temperatures at the two ends. Assuming steady one-dimensional heat

conduction, which of the following statements is true about the respective thermal

conductivities?

(A) 2k1 = k2

(B) k1=k2

(C) 2k1 = 3k2

(D) k1 = 2k2

12. In a Pelton wheel, the bucket peripheral speed is 10 m/s, the water jet velocity is 25 m/s

and volumetric flow rate of the jet is 0.1 m3 Is. If the jet deflection angle is 1200 and the flow

is ideal, the owe developed is:

(A) 7.5 kW

(B) 15.0 kW

(C) 22.5 kW

(D) 37.5 kW

13. An expendable pattern is used in

(A) slush casting

(B) squeeze casting

(C) centrifugal casting

(D) investment casting

14. The main purpose of spheroidising treatment is to improve

(A) harden-ability of low carbon steels

(B) mach-inability of low carbon steels

(C) harden-ability of high carbon steels

(D) mach-inability of high carbon steels

15. NC contouring is an example of

(A) continuous path positioning

(B) point-to-point positioning

(C) absolute positioning

(D) incremental positioning

16. A ring gage is used to measure

(A) outside diameter but not roundness

(B) roundness but not outside diameter

(C) both outside diameter and roundness

(D) only external threads

17. The number of customers arriving at a railway reservation counter is Poisson distributed

with an arrival rate of eight customers per hour. The reservation clerk at this counter takes six

minutes per customer on an average with an exponentially distributed service time. The

average number of the customers in the queue will be

(A) 3

(B) 3.2

(C) 4

(D) 4.2

18. In an MRP system, component demand is:

(A) forecast-ed

(B) established by the master production schedule

(C) calculated by the MRP system from the master production schedule

(D) ignored

Q.21 to Q.75 Carry Two Marks Each.

19. Eigen values of a matrix

s [ jare 5 and 1. What are the eigen values of the matrix S2 = SS?

(A) 1 and 25

(B) 6 and 4

(C) 5 and 1

(D) 2 and 10

20. Equation of the line normal to function

f(x)=(x-8)+1 atP(0,5)is:

(A) y=3x—5

(B) y=3x+5

(C) 3y=x+15

(D) 3y=x—15

21. Assuming i = and t is a real number, [edt is:

(A)

2 2

(B)

2 2

(C)

(D)

22. If f(x) 2x2 —7x+3 , then limf(x)will be

5x2—12x—9

(A)

(B)

18

(C) 0

(D)

23. Match the items in columns I and II.

Col umn I Column II

(P) Addendum (1) Cam

(Q) Instantaneous center of velocity (2) Beam

(R) Section modulus (3) Linkage

(S)

Prime circle (4) Gear

(A) P - 4 Q - 2 R - 3 5 - 1

(B) P - 4 Q - 3 R - 2 S - 1

(C) P - 3 Q - 2 R - 1 S - 4

(D) P - 3 Q - 4 R - 1 5 – 2

24.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

25. Twenty degree full depth involute profiled 19-tooth pinion and 37-tooth 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

26. A cylindrical shaft is subjected to an alternating stress of 100 MPa. Fatigue strength to

sustain 1000 cycle 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

27. According to Von-Mises’ distortion energy theory, the distortion energy under three

dimensional stress state is represented by

(A) [u +u +u -2v(u1u2 ±32±13)1

1—2v 2 2 2

(B) 6E [u1 +j2 +o +2v(u1u2 +J3J2 +u1u3)

1+v 2 2 2

(C) —--— [o + + — (u1u2 + ° + oo )

(D) —_- [u + + — v (uu2 + + cro )

28. A steel bar of 40 mm x 40 mm square cross-section is subjected to an axial compressive

load of 200 kN. If the length of the bar is 2m and E = 200 GPa, the elongation of the bar will

be:

(A) 1.25 mm

(B) 2.70 mm

(C) 4.05 mm

(D) 5.40 mm

29. If Cf is the coefficient of speed fluctuation of a flywheel then the ratio of will be:

(A) 1—2Cf 1 + 2Cf

(B) 2C, 2+ Cf

(C) l+2Cf l—2Cf

(D) 2+Cf 2- Cf

30. A bar having a cross-sectional area of 700 mm2 is subjected to axial loads at the positions

indicated. The value of stress in the segment QR is:

(A) 40 MPa

(B) 50 MPa

(C) 70 MPa

(D) 120 MPa

31. If a system is in equilibrium and the position of the system depends upon many

independent variables, the principle of virtual work states that the partial derivatives of its

total potential energy with respect to each of the independent variable must be

(A) -1.0

(B) 0

(C) 1.0

(D)

32. If point A is in equilibrium under the action of the applied forces, the values of tensions

TAB and TAC are respectively.

(A) 520 N and 300 N

(B) 300 N and 520 N

(C) 450 N and 150 N

(D) 150 N and 450 N

33. Match the items in columns I and II

Column I Column II

(P) Higher kinematic pair (1) Grubler’s equation

(Q) Lower kinematic pair (2) Line contact

(R) Quick return mechanism (3) Euler’s equation

(S) Mobility of a linkage AT (4) Planer

(5) Shaper

(6) Surface contact

(A) P - 2 Q - 6 R - 4 5 - 3

(B) P - 6 Q - 2 R - 4 5 - 1

(C) P - 6 Q - 2 R - 5 S - 3

(D) P - 2 Q - 6 R - 5 5 – 1

34.A machine of 250 kg mass is supported on springs of total stiffness 100 kN/m.

Machine has an unbalanced rotating force of 350 N at speed of 3600 rpm.

Assuming a damping factor of 0.15, the value of transmissibility ratio is:

(A) 0.0531

(B) 0.9922

(C) 0.0162

(D) 0.0028

35. In a four-bar linkage, S denotes the shortest link length, L is the longest link length, P and

Q are the lengths of other two links. At least one of the three moving links will rotate by 360°

if

(A) S+LP+Q

(B) S+L>P+Q

(C) S+PL+Q

(D) S+P>L+Q

36. A 60 mm long and 6 mm thick fillet weld carries a steady load of 15 kN along the

weld. The shear strength of the weld material is equal to 200 MPa. The factor of

safety is

(A) 2.4

(B) 3.4

(C) 4.8

(D) 6.8

37. A two-dimensional flow field has velocities along the x and y directions given by u = x2t

and v = -2xyt respectively, where t is time. The equation of streamlines is:

(A) x2y = constant

(B) xy2 = constant

(C) xy = constant

(D) not possible to determine

38. The velocity profile in fully developed laminar flow in a pipe of diameter D is given by u =

u0 (1 _4r2/D2), where ris the radial distance from the center. If the viscosity of the fluid is p,

the pressure drop across a length L of the pipe is:

(A) pu0L

D2

(B) 4pu0L

D2

(C) 8pu0L

D2

(D) l6pu0L

D2

39. A siphon draws water from a reservoir and discharges it out at atmospheric pressure.

Assuming ideal fluid and the reservoir is large, the velocity at point P in

the siphon tube is: P

7’

(A)1/

(B) h1

h2

(C) .J2g(h2—h1)

(D) .,J2g(h2+h1)

40. A large hydraulic turbine is to generate 300 kW at 1000 rpm under a head of 40 m. for

initial testing, a 1:4 scale model of the turbine operates under a head of 10 m. the power

generated by the model (in kW) will be

(A) 2.34

(B) 4.68

(C) 9.38

(D) 18.75

41. The statement concern psychrometric chart.

1. Constant relative humidity lines are uphill straight lines to the right

2. Constant wet bulb temperature lines are downhill straight lines to the right.

3. Constant specific volume lines are downhill straight lines to the right.

4. Constant enthalpy lines are coincident with constant wet bulb temperature lines.

Which of the statements are correct?

(A) 2 and 3

(B) 1 and 2

(C) 1 and 3

(D) 2 and 4

42. A 100 W electric bulb was switched on in a 2.5 m x 3 m x 3 m size thermally

insulated room having a temperature of 20°C. The room temperature at the end

of 24 hours will be

(A) 321 °C

(B) 341 °C

(C) 450 °C

(D) 470 °C

43. A thin layer of water in field is formed after a farmer has watered it. The ambient air

conditions are: temperature 20 °C and relative humidity 5%.

An extract of steam tables is given below.

Temperature (°C) -15 -10 -5 0.01 5 10 15 20

Neglecting the heat transfer between the water and the ground, temperature in the field after

phase equilibrium is reached equals

(A) 10.3 °C

(B) -10.3 °C

(C) -14.5 °C

(D) 14.5 °C

44. A horizontal shaft centrifugal pump lifts ware at 65°C. The suction nozzle is one meter

below pump centerline. The pressure at this point equal 200 kPa gauge and velocity is 3 m/s.

Steam tables.show saturation pressure at 65°C is 25 kPa, and specific volume of the saturated

liquid is 0.001020 m3/kg. The pump Net

(A) 24

(B) 26

(C) 28

45. Given below is an extract from steam tables.

Specific enthalpy of water in kJ/kg at 150 bar and 45 °C is

(A) 203.60

(B) 200.53

(C) 196.38

(D) 188.45

46. Determine the correctness or otherwise of the following Assertion [a] and the Reason [r].

Assertion [a]: In a power plant working on a Ranking cycle, the regenerative feed water

heating improves the efficiency of the steam turbine.

Reason [r]: The regenerative feed water heating raises the average temperature of heat

addition in the Rankine cycle.

(A) Both [a] and [r] are true and [r]. is the correct reason for [a].

(B) Both [a] and [r] are true but [r] is NOT the correct reason for [a].

(C) Both [a] and [r] are false

(D) [a] is false and [r] is true.

47. Determine the correctness or otherwise of the following Assertion [a] and the Reason [r].

Assertion [a]: Condenser is an essential equipment in a steam power plant.

Reason [r]: For the same mass flow rate and the same pressure rise, a water

pump requires substantially less power than a steam compressor.

(A) Both [a] and [r] are true and [r] is the correct reason for [a].

(B) Both [a] and [r] are true but [r] is NOT the correct reason for [a].

(C) [a] is true but [r] is false

(D) [a] is false and [r] is true.

48. Match items from groups I, II, III, IV and V.

Temperature(°C)sa(bar)Specific volume (m31kg) Enthalpy (kJ/kg)SaturatedliquidSaturatedvapourSaturatedliquidSa turatedvapour

49.0.09593 0.001010 15.26 188.45 2394.8

342.24 150 0.001658 0.010337 1610.5 2610.5

(A) F - G - J - K - M E-G -I-K-N

(B) E - G - I - K - M F-H -I-K-N

(C) F — H - J - L — N E-H -I-L-M

(D) E - G - J - K - N F-H -J-K-M

50. Group I shows different heat addition processes in power cycles. Likewise, Group II shows

different heat removal processes. Group III lists power cycles. Match items from Groups I, II

and III[\ b

GroupIGroup II Group III GroupIVGroup V

When added to the system,isDifferential

Function Phenomenon

E Heat G Positive I Exact K Path M Transient

F Work H Negative J Inexact L Point N Boundary

Group I Group II G roup III

P. Pressure constant S. Pressure constant 1. Rankine cycle

Q. Volume constant T. Volume constant 2. Otto cycle

R. Temperature constant U. Temperature constant 3.

4.

5.

(A) P—S—5, R— U—3, P—S— i,Q—T-2

(B) P—S—i, R— U—3, P—S—4, P—T-2

(C) R-T-3,P-S-i,P-T-4,Q-S-5

(D) P—T—4, R—S—3,P—S— i, P—S-S

Carnot cycleDiesel cycleBrayton cycle

51. With an increase in thickness of insulation aroundasurroundings due to

(A) convection increases, while that due to conduction

(B) convection decreases, while that due to conduction

(C) convection and conduction decreases

(D) convection and conduction increasescircular pipe,heatdecreasesincreasesloss to

52. The ultimate tensile strength of a material is 400 MPa and the elongation up to maximum

load is 35°h. If the material obeys power law of hardening, then the true stress-true strain

relation (stress in MPa) in the plastic deformation range is:

(A) u = 540s°°

(B) u = 775s°3°

(C) u = 540s°5

(D) u = 775s°35

53. In a sand casting operation, the total liquid head is maintained constant such that it is

equal to the mould height. The time taken to fill the mould with a top gate is tA If the same

mould is filed with a bottom gate, then the time taken is t8. Ignore the time required to fill the

runner and frictional effects. Assume atmospheric pressure at the top molten metal surfaces.

The relation between tA and t8 is:

(A) tB=JtA

(B) tB=2tA

(C) t8 = - - -

(D) tB=2%JtA

54. A 4 mm thick sheet is rolled with 300 mm diameter rolls to reduce thickness without any

change in its width. The friction coefficient at the work-roll interface is 0.1. The minimum

possible thickness of the sheet that can be produced in a single pass is:

(A) 1.0 mm

(B) 1.5 mm

(C) 2.5 mm

(D) 3.7 mm

55. In a wire drawing operation, diameter of a steel wire is reduced from 10 mm to 8 mm. the

mean flow stress of the material is 400 MPa. The ideal force requied for drawing (ignoring

friction and redundant work) is:

(A) 4.48 kN

(B) 8.97 kN

(C) 20.11 kN

(D) 31.41 kN

56. If each abrasive grain is viewed as a cutting tool, then which of the following represents

the cutting parameters in common grinding operations?

(A) Large negative rake angle, low shear angle and high cutting speed

(B) Large positive rake angle, low shear angle and high cutting speed

(C) Large negative rake angle, high shear angle and low cutting speed

(D) Zero rake angle, high shear angle and high cutting speed

57. In an arc welding process, the voltage and current are 25 V and 300 A respectively. The

arc heat transfer efficiency is 0.85 and welding speed is 8 mm/sec. the net heat input (in

J/mm) is:

(A) 64

(B) 797

(C) 1103

(D) 79700

58. Arrange the processes in the increasing order of their maximum material removal rate.

Column I Column II

(P) Wrinkling (1) Yield point elongation

(Q) Orange peel (2) Anisotropy

(R) Stretcher

strains

(3) Large grain size

(5) Earing (4) Insufficient blank holding force

(5) Fine grain size

(65) Excessive blank holding force

(A) P - 4 Q - 5 R - 3 5 - 2

(B) P - 3 Q - 5 R - 1 S - 4

(C) P - 2 Q - 4 R - 3 5 - 5

(D) P - 4 Q - 2 R - 1 5 – 3

59. A manufacturing shop processes sheet metal jobs, wherein each job must pass through

two machines (Ml and M2, in that order). The processing time (in hours) for these jobs is:

The optimal make-span (in hours) of the shop is:

(A) 120

(B) 115

(C) 109

(D) 79

60. Consider the following data for an item.

Column I Column II

(P) Charpy test (1) Fluidity

(Q) Knoop test (2) Microhardness

(R) Spiral test (3) Formability

(S) Cuppingtest

(4) Toughness

(5) Permeability

Machine JobsP Q R ST U

Ml 15 32 8 27 11 16

M2 6 19 13 20 14 7

Price quoted by a supplier

Annual demand: 2500 units per year

Ordering cost: Rs.100 per order

Inventory holding rate: 25% of unit price.

The optimum order quantity (in units) is:

(A) 447

(B) 471

(C) 500

(D) 600

61. A firm is required to procure three items (P, Q and R). The prices quoted for these items

(in Rs.) by suppliers Si, S2 and S3 are given in table. The management policy requires that

each? item has to be supplied by only one supplier and one supplier supply only one item. The

minimum total cost (in Rs.) of procurement to the firm is:

(A) 350

(B) 360

(C) 385

(D) 395

62. A stockist wishes to optimize the number of perishable items he needs to stock in any

month in his store. The demand distribution for this perishable item is:

Order quantity

(units)

Unit price (Rs.)

< 500 10

500 9

Item

Suppliers

Si S2 S3

P 110 120 130

Q 115 140 140

R 125 145 165

Demand (in units)

2Probability 0.130.3540.3550.20

The stockist pays Rs.70 for each item and he sells each at Rs.90. if the stock is left unsold in

any month, he can sell the item at Rs.50 each. There is no penalty for unfulfilled demand. To

maximize the expected profit, the optimal stock level is:

(A) 5 units

(B) 4 units

(C) 3 units

(D) 2 units

63. The table gives details of an assembly line.Work station I II III IV V VI

Total task time at the workstation (in minutes) 7 9 7 10 9 6

What is the line efficiency of the assembly line?

(A) 70°h

(B) 75°h

(C) 80°h

(D) 85°h

Common Data Questions

Common Data for Questions 71, 72, 73:

In an orthogonal machining operation:

Uncut thickness = 0.5 mm Cutting speed = 20 m/min

Width of cut = 5 mm Chip thickness = 0.7 mm

Thrust force = 200 N Cutting force = 1200 N

Rake angle = 15°

Assume Merchant’s theory.

64. The values of shear angle and shear strain, respectively, are

(A) 30.3° and 1.98

(C) 40.2° and 2.97

(D) 40.2° and 1.65

65. The coefficient of friction at the tool-chip interface is:

(A) 0.23

(B) 0.46

(C) 0.85

(D) 0.95

66. The percentage of total energy dissipated due to friction at the tool-chip interface

is:

(A) 30°h

(B) 42°h

(C) 58°h

(D) 70°h

Common Data for Questions 74, 75:

A planetary gear train has four gears and one carrier. Angular velocities of the gears are

(1JO2,(O3 and o4 respectively. The carrier rotates with angular velocity (05•

40T

74. What is the relation between the angular velocities of Gear 1 and Gear 4?

(A) 15_6 (04 — (05

(B) 04 (0 =6 (V -(t

(C) 12 =—i:•-: (04—a)3 3

(D)

75. For a = 60 rpm clockwise (cw) when looked from the left, what is the angular velocity of

the carrier and its direction so that Gear 4 rotates in counterclockwise (ccw) direction at twice

the angular velocity of Gear 1 when looked from the left

(A) 130 rpm, cw

(B) 223 prm, ccw

(C) 256 rpm, cw

(D) 156 rpm, ccw

Linked Answer Questions: Q.76 to Q85 Carry Two Marks Each

Statement for Linked Answer Questions 76 & 77:

A simply supported beam of span length 6 m and 75 mm diameter carries a uniformly

distributed load of 1.5 kN/m.

76. What is the maximum value of bending moment?

(A) 9 kNm

(B) 13.5 kNm

(C) 81 kNm

(D) 125 kNm

77. What is the maximum value of bending stress?

(A) 162.98 MPa

(B) 325.95 MPa - -

(C) 625.95 MPa I

(d) 651.90 MPa

Statement for Linked Answer Questions 78 & 79:

A vibratory system consists of a mass 12.5 kg, a spring of stiffness 1000 N/m, and a dashpot

with damping coefficient of 15 Ns/m.

78. The value of critical damping of the system is:

(A) 0.223 Ns/m

(B) 17.88 Ns/m

(C) 71.4 Ns/m

(D) 223.6 Ns/m

79. The value of logarithmic decrement is:

(A) 1.35

(B) 1.32

(C) 0.68

(D) 0.66

Statement for Linked Answer Questions 80 & 81:

A football was inflated to a gauge pressure of 1 bar when the ambient temperature was

15°C. When the game started next day, the air temperature at the stadium was 5°C.

Assume that the volume of the football remains constant at 2500 cm3.

80. The amount of heat lost by the air in the football and the gauge pressure of air in

the football at the stadium respectively equal

(A) 30.6], 1.94 bar

(B) 21.8], 0.93 bar

(C) 61.1], 1.94 bar

(D) 43.7], 0.93 bar

81. Gauge pressure of air to which the ball must have been originally inflated so that it would

equal 1 bar gauge at the stadium is:

(A) 2.23 bar

(B) 1.94 bar

(C) 1.07 bar

(D) 1.00 bar

Statement for Linked Answer Questions 82 & 83:

A smooth flat plate with a sharp leading edge is placed along a gas stream flowing at U

= 10 m/s. The thickness of the boundary layer at section r — s is 10 mm, the breadth of

the plate is 1 m (into the paper) and the density of the gas p = 1.0 kg/m3. Assume that

the boundary layer is thin, two-dimensional, and follows a linear velocity distribution,

u = U(y/S), at the section r —s, where yis the height from plate.

82. The mass flow rate (in kg/s) across the section q—ris:

(A) zero

(B) 0.05

(C) 0.10

(D) 0.15

83. The integrated drag force (in N) on the plate, between p—s, is:

(A) 0.67

(B) 0.33

(C) 0.17

(D) zero

Statement for Linked Answer Questions 84 & 85:

Consider a PERT network for a project involving six tasks (a to f).

84. The expected completion time of the project is:

(A) 238 days

(B) 224 days

(C) 171 days

(D) 155 days

85. The standard deviation of the critical path of the project is:

(A) Jii days

(B) /i days

(C) Jöö days

(D) days

Task Predecessor Expected task time (indays)Variance of the task time (in days2)

a - 30 25

b a 40 64

c a 60 81

d b 25 9

e b,c 45 36

f d,e 20 9