SECTION-6

MACHINE DESIGN MCQ

##### Q61. For a hollow shaft of external diameter D and internal diameter d, the modulus of section is equal to

(a)  π( D4-d 4 )/64D
(b)  π( D4-d 4 )/32D
(c)  π( D4-d 4 )/16D
(d)  π( D4+d 4 )/32D

Ans:(b)  π( D4-d 4 )/32D

##### Q62. For a hollow shaft of external diameter D and internal diameter d the polar modulus of section is equal to

(a)  π( D4-d 4 )/64D
(b)  π( D4-d 4 )/32D
(c)  π( D4-d 4 )/16D
(d)  π( D4+d 4 )/32D

Ans:(c)  π( D4-d 4 )/16D

##### Q63. In case of a flange coupling the width of the flange varies from

(a) D to D + 1.25
(b) 1.5 D to l.5 D + 1.25
(c)  D/2 to D/2  + 1.25
(d) D/4 to D/4  + 1.25

Ans:(c)  D/2 to D/2  + 1.25

(a) 0.5 D
(b) 1.0 D
(c) 1.5 D
(d) 3.0 D.

Ans:(c) 1.5 D

##### Q65.In case of a flange coupling usually a rectangular key is used, the width (b) and thickness (t) of the rectangular key are taken as

(a) b =D/4and t = 2D/3
(b) b =D/3and t = 2D/3
(c) b =D/4and t = D/6
(d) t =D/2 and t = D/6

Ans:(c) b =D/4and t = D/6

##### Q66. Power transmitted by a belt in S.I. unit is given by

(a)  T1 × V Watt
(b)  T2 × V
(c)  ( T1 −T 2 ) ×V/1000  kW
(d) ( T1 +T 2 ) ×V/1000
.where T1 = Tension on tight side, T2 = Tension on slack side, V = Velocity in m/sec.

Ans:(c)  ( T1 −T 2 ) ×V/1000  kW

##### Q67. The centrifugal tension acting on a rotating bell is given by

(a) Tc = 1/ 2   mV2
(b) Tc = mV2
(c) Tc = 2W/g  V2
(d) Tc =  3W/g  × V2
where W= Weight of belt per unit length, V = Linear velocity of belt, and
Tc = Centrifugal tension.

Ans:(b) Tc = mV2

##### Q68. The friction circle of a bearing is having radius equal to

(a) r
(b) r cos φ
(c) r sin φ
(d) r tan φ.
where r = Radius of shaft, and φ = Angle of friction.

Ans:(c) r sin φ

##### Q69. If failure in shear along 45° planes is to be avoided, then a material subjected to uniaxial tension should have its shear strength equal to at least

(a) tensile strength
(b) compressive strength
(c) half the difference between the tensile and compressive strengths
(d) half the tensile strength.                                                                                (IES 1994)

Ans:(c) half the difference between the tensile and compressive strengths

##### Q70. The bearing characteristic number is given by

(a) Z ×p/N
(b) Z ×N/p
(c) p / Z ×N
(d) Z/p × N .
where Z = Absolute viscosity of lubricant in centipoise, N = Speed, and
p = Pressure in N/mm2.

Ans:(b) Z ×N/p

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##### Read More Sections of Machine Design

Each section contains maximum 80 Questions. To practice more questions visit other sections.

Machine Design MCQ – Section-1

Machine Design MCQ – Section-2

Machine Design MCQ – Section-3

Machine Design MCQ – Section-4

Machine Design MCQ – Section-5

Machine Design MCQ – Section-6

Machine Design MCQ – Section-7