SECTION-7

MACHINE DESIGN MCQ

##### Q1. If the size of a standard specimen for a fatigue testing machine is increased, the endurance limit for the material will

(a) have same value as that of standard specimen

(b) increase

(c) decrease

Ans: (c) decrease

##### Q2. Stress concentration factor is defined as the ratio of

(a) maximum stress to the endurance limit

(b) nominal stress to the endurance limit

(c) maximum stress to the nominal stress

(d) nominal stress to the maximum stress

Ans: (c) maximum stress to the nominal stress

##### Q3. The fatigue stress concentration factor is defined as

(a) the ratio of endurance limit with stress concentration to the endurance limit without stress concentration

(b) the ratio of endurance limit without stress concentration to the endurance limit with stress concentration

(c) the product of the endurance limits with and without stress concentration

(d) all of the above

Ans: (b) the ratio of endurance limit without stress concentration to the endurance limit with stress concentration

##### Q4. The design calculations for members subject to fluctuating loads with the same factor of safety, yield the most conservative estimates when using

(a) Gerber relation

(b) Soderberg relation

(c) Good man relation

(d) none of these

Ans: (c) Good man relation

##### Q5. In case of pressure vessels having closed ends, the fluid pressure induces

(a) longitudinal stress

(b) circumferential stress

(c) shear stress

(d) none of these

Ans: (d) none of these

##### Q6. Which of the following statements is correct?

(a) Flywheel reduces speed fluctuations during a cycle for a constant load, but flywheel does not control the mean speed of the engine if the load changes.
(b) Flywheel does not reduce speed fluctuations during a cycle for a constant load, but flywheel does  control the mean speed of the engine if the load changes.
(c) Governor controls speed fluctuations during a cycle for a constant load, but governor does not control the mean speed of the engine if the load changes.
(d) Governor controls speed fluctuations during a cycle for constant load, and governor also controls the mean speed of the engine if the load changes.                                                (GATE 2001)

Ans:(a) Flywheel reduces speed fluctuations during a cycle for a constant load, but flywheel does not control the mean speed of the engine if the load changes.

##### Q7. The endurance limit of a material subject to fatigue loading

(a) increases with the increase of ultimate strength
(b) increases with the decrease of ultimate strength
(c) in independent of ultimate strength
(d) none of the above.

Ans:(a) increases with the increase of ultimate strength

##### Q8. If the rotating mass of a rim type flywheel is distributed on another rim type flywheel whose mean radius is half mean radius of the former, the energy stored in the latter at the same speed will be

(a) four times the first one
(b) same as the first one
(c) one-fourth of the first one
(d) one and half times the first one.                                                          (IES 1993)

Ans:(c) one-fourth of the first one

##### Q9. A metal pipe of 1.0 m diameter is filled with a fluid having a pressure of 10 kg/cm2. If the permissible tensile stress in the metal is 200 kg/cm2, then the thickness of the metal required for making the pipe would be

(a) 5 mm
(b) 10 mm
(c) 20 mm
(d) 25 mm.                                                                                   (IES 1993)

Ans:(d) 25 mm

##### Q10. A vertical shaft of dia. 150 mm carries a vertical load of 20 kN and rests flat foot-step bearing. The shaft is rotating at 100 r.p.m. and μ = 0.045. For uniform pressure distribution, the frictional torque will be

(a) 25 Nm
(b) 35 Nm
(c) 45 Nm
(d) 55 Nm.

Ans:(c) 45 Nm

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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