2 Apr 2025
Cos BL Q.N Questions Marks Marking Scheme Correct Answer
 

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1

 The taper oncotter variesfrom

A.1inl5to 1 in10      B.1 in24 to 1in 20

C.1in20 to1in 10     D.1 in 48 to1in 24

  

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D
 

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2

 When the fulcrum is in between the load and effort, the lever is said to be of                                                                                                                                                                        A.first type

B.secondtype

  

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A
C303.1 1 3 Thecross-sectionofthearm ofabellcranklever is

A.rectangular      B.elliptical      C.I-section      D. any one of these

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D
 

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4

 Thediameterofknucklepinintheknucklejointisusually… A.0.5d            B.0.8d             C.1.5d                   D.d  

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D
 

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5

 Thebellcrankleversusedinrailwaysignalingarrangementareofthirdtype levers.

A.True       B.False

  

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A
 

 

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6

 Designaknuckle jointto connect two circularMSrodswhichare subjectedto atensileload of 63 kN. The allowable stresses are 80 MPa in tension, 56 MPa inshear and 80 MPa in crushing.Find the Diameter of Rod

A.30     B.52    C.26      D.NoneOfThese

  

 

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2mark each

  

 

 

 

D
 

 

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7

  

In the levers of third type, the mechanical advantage is                           one. A.Less than

B.Equalto

C.Morethan

D.Noneof these

  

 

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A
 

 

 

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8

 If knuckle joint is to fail by crushing failure of pin in fork, then determine the diameter of knuckle pinwhen 50kNaxialtensile force act onrods. Given: Max allowable compressive stress=25N/mm², thickness of each eye of fork=25mm.

A)  40mm

B)  50mm

C)  60mm

D)  70mm

  

 

 

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A
 

 

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9

 Calculate the diameter of pinfrom shear considerationwithmaximum shear stress allowedis 40NN/mm² and an axial tensile force of 50kN is acting on the rod.

A)  39mm

B)  44mm

C)  49mm

D)  52mm

  

 

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A
 

 

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10

 Aknucklejointcanbeusedinvalvemechanismofareciprocatingengine.

A)  Yes

B)  No

C)  Yesbuttherearestressprobles

D)  Noasitisverydangerousto use

  

 

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A
C303.1 3 11 Aknucklejointisunsuitablefortworotatingshafts,whichtransmit torque

A.2    B.3    C.4   D.5

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B
 

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12

 Aknucklejointisunsuitablefortworotatingshafts,whichtransmittorque A.True

B False

  

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B
 

 

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13

 TheconstantfactorincaseofR10seriesofpreferrednumbersis A.1.06

B.1.12

C.1.26

D. 1.58

  

 

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C
 

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14

 Ashaftisdesignedonthebasisofrigidityandstiffness.

A.  Correct

B.  Incorrect

  

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B

 

 

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15

 A crankshaft is a                           shaft.

A.  transmission

B.  machine

  

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B
 

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16

 Indesigningaflangecoupling,thepitchcirclediameterofboltsistakenas(where d= Diameter of the shaft)

A.2d     B.3 d

C.4 d     D.5 d

  

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A
 

 

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17

 Whichofthefollowingstatementis correct?

A.  Aparallelsunkkeyisataperlesskey

B.  Aparallelsunkkeymayberectangularorsquareincross-section

C.  Aflatsaddlekey isataperkeywhichfitsinakeyway ofthehubandisflatonthe shaft

D.  allof the above

  

 

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A
 

 

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18

 Acouplingusedtoconnecttwoperfectlyalignedshafts,is

A.  muffcoupling

B.  compressioncoupling

C.  flangecoupling

D.  allofthese

  

 

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D
 

 

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19

 Forasquarekey madeofmildsteel,theshearandcrushingstrengtharerelatedas

A.  shearstrengthisequaltocrushing strength

B.  shearstrengthisgreaterthancrushingstrength

C.  shearstrengthislessthancrushingstrength

D.  noneof the above

  

 

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B
 

 

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20

 Inaflangecoupling,theflangesarecoupledtogetherbymeansof

A.  boltsandnuts

B.  studs

C.  headlesstaperbolts

D.  none of these

  

 

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A
 

 

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21

 Maximumshearstresstheory isusedfor

A)  Castironshafts

B)  Steel shafts

C)  Flexibleshafts

D)  Plastic shafts

  

 

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B

 

 

 

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22

 Splinesarecommonlyusedin

A)  Machinetoolgearbox

B)  Automobilegearbox

C)  Hoistandcranegearbox

D)  Bicycle

  

 

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B
 

 

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23

  

The bendingmoment ‘M’anda torque ‘T’is applied ona solidcircularshaft. If the maximum bending stress equals to maximum shear stress developed, then ‘M’is equal to

A.T/2         B.T

C.2 T          D.4T

  

 

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A
 

 

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24

 TransmissionshaftincludesOverheadshaft

A)Overheadshaft

(B)  Countershaft

(C)  Lineshaft

(D)  All of these

  

 

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D
 

 

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25

 Two shafts A andB are made of same material.The diameter of shaft A is twice that of B. The torque transmitted by shaft A will be

A)  Twice that ofB

B)  Fourtimesthatof B

C)  Eighttimesthat of B

D)  Sixteentimesthat of B

  

 

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C
 

 

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26

 Thecompressivestressinducedinasquarekey is,

A)  Equaltoshearstress

B)  Fourtimesofshear stress

C)  Twice of shearstress

D)  Halfofshear stres

  

 

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C
 

 

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27

 The maximum shear stress induced ina transmissionshaft, subjectedto bendingstress (σb) and torsional shear stress (τ), is given by,

A)  √[(σb/2)2+τ2]

B)  √[σb2+τ2]

C)  σb/2+½√[(σb/2)2+ τ2]

D)  Noneof above

  

 

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A