SECTION-4

##### Q41. The thickness of the projected portion of the flange may vary from

(a) 10 mm to 15 mm
(b) 15 mm to 20 mm
(c) 20 mm to 25 mm
(d) 5 mm to 8 mm.

Ans:(d) 5 mm to 8 mm.

##### Q42. The number of bolts by empirical formula in a flange coupling is given by

(a) n =D/2  + 3
(b) n =D/5   + 3
(c) n = 3D/4  + 3
(d) n =2D/7  + 3
where D = Diameter of solid shaft in cm.

Ans:(b) n =D/5   + 3

(a) 2
(b) 3
(c) 4
(d) 5.

Ans:(b) 3

##### Q44. The power transmitted by a belt is maximum when initial tension in the belt is

(a) half of centrifugal tension
(b) one-third of centrifugal tension
(c) twice of centrifugal tension
(d) three times the centrifugal tension.

Ans:(d) three times the centrifugal tension.

##### Q45. The angle of lap on the smaller pulley for open belt is given by

$\text { (a) } 180^{\circ}-2 \sin ^{-1}\left(\frac{r_{1}-r_{2}}{d}\right)$

$\text { (b) } 180^{\circ}-2 \cos ^{-1}\left(\frac{r_{1}-r_{2}}{d}\right)$

$\text { (c) } 180^{\circ}-2 \sin ^{-1}\left(\frac{r_{1}+r_{2}}{d}\right)$

$\text { (d) } 180^{\circ}-2 \cos ^{-1}\left(\frac{r_{1}+r_{2}}{d}\right)$

where r1 = Radius of large pulley, r2 = Radius of small pulley, and
d = Centre distance between the shafts.

Ans:$\text { (a) } 180^{\circ}-2 \sin ^{-1}\left(\frac{r_{1}-r_{2}}{d}\right)$

##### Q46. The relation between initial tension (T0), tension on tight side (T1) and tension on slack side (T2) (if the material of the belt is not perfectly elastic) is given by

$(a) T_{0}=\sqrt{T_{1}}+\sqrt{T_{2}}$

$\text { (b) } T_{0}=\frac{\sqrt{T_{1}}+\sqrt{T_{2}}}{2}$

$\text { (c) } \sqrt{T_{0}}=\frac{\sqrt{T_{1}}+\sqrt{T_{2}}}{2}$

$\text { (d) } T_{0}=\sqrt{T_{1}}+\sqrt{T_{2}} \text {. }$

Ans:$\text { (b) } T_{0}=\frac{\sqrt{T_{1}}+\sqrt{T_{2}}}{2}$

##### Q47. If P is the axial load and σt is the permissible tensile stress in the material of the two co-axial rods connected by cotter joint, then diameter of the rods is given by

$\text { (a) } \sqrt{\frac{\pi P}{4 \sigma_{t}}}$

$\text { (b) } \sqrt{\frac{4 P}{\pi \times \sigma_{t}}}$

$\text { (c) } \sqrt{\frac{4 \sigma_{t}}{\pi P}}$

$(d) \sqrt{\frac{\pi \times \sigma_{t}}{4 P}} .$

Ans:$\text { (b) } \sqrt{\frac{4 P}{\pi \times \sigma_{t}}}$

##### Q48. The frictional torque transmitted by a disc clutch for a single friction surface considering uniform wear is equal to

$\text { (a) } \frac{2}{3} \mu W \frac{\left(r_{1}^{2}-r_{2}^{2}\right)}{\left(r_{1}^{3}-r_{2}^{3}\right)}$

$\text { (b) } \frac{2}{3} \mu W \frac{\left(r_{1}^{3}-r_{2}^{3}\right)}{\left(r_{1}^{2}-r_{2}^{2}\right)}$

$\text { (c) } \frac{1}{2} \pi W\left(r_{1}-r_{2}\right)$

$(d) \frac{1}{2} \pi W\left(r_{1}+r_{2}\right)$

Ans:$(d) \frac{1}{2} \pi W\left(r_{1}+r_{2}\right)$

##### Q49. A cotter is used to

(a) rigidly connect rods
(b) transmit motion
(c) prevent rotation of rods
(d) all of the above
(e) none of the above.

Ans:(a) rigidly connect rods

##### Q50. For connecting piston rod and cross-head of an engine

(a) a cotter joint is used
(b) a knuckle joint is used
(c) both are used
(d) none is used.

Ans:(a) a cotter joint is used

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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