NDA - Theory of Machines 1000+ MCQ [Solved] PDF Download
Thursday 9th of March 2023
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1. In a system subjected to damped forced vibrations, the ratio of maximum displacement to the static deflection is known as
A. Critical damping ratio
B. Damping factor
C. Logarithmic decrement
D. Magnification factor
Answer : D
A. Critical damping ratio
B. Damping factor
C. Logarithmic decrement
D. Magnification factor
Answer : D
2. When a body is subjected to transverse vibrations, the stress induced in a body will be
A. Shear stress
B. Bending stress
C. Tensile stress
D. Compressive stress
Answer : B
A. Shear stress
B. Bending stress
C. Tensile stress
D. Compressive stress
Answer : B
3. In involute gears, the pressure angle is
A. Dependent on the size of teeth
B. Dependent on the size of gears
C. Always constant
D. Always variable
Answer : C
A. Dependent on the size of teeth
B. Dependent on the size of gears
C. Always constant
D. Always variable
Answer : C
4. Which of the following is a turning pair?
A. Piston and cylinder of a reciprocating steam engine
B. Shaft with collars at both ends fitted into a circular hole
C. Lead screw of a lathe with nut
D. Ball and a socket joint
Answer : B
A. Piston and cylinder of a reciprocating steam engine
B. Shaft with collars at both ends fitted into a circular hole
C. Lead screw of a lathe with nut
D. Ball and a socket joint
Answer : B
5. In a differential band brake as shown in the below figure, the drum rotates anticlockwise and the greater tension T? acts at A and smaller tension T? at B. Length OA is greater than length OB. In order to apply the brake, the force P at C should 
A. Be zero
B. Act in upward direction
C. Act in downward direction
D. None of the above
Answer : C
A. Be zero
B. Act in upward direction
C. Act in downward direction
D. None of the above
Answer : C
6. When a point at the end of a link moves with constant angular velocity, its acceleration will have
A. Radial component only
B. Tangential component only
C. Coriolis component only
D. Radial and tangential components both
Answer : A
A. Radial component only
B. Tangential component only
C. Coriolis component only
D. Radial and tangential components both
Answer : A
7. Higher pairs are those which have
A. Point or line contact between the two elements when in motion
B. Surface contact between the two elements when in motion
C. Elements of pairs not held together mechanically
D. Two elements that permit relative motion
Answer : A
A. Point or line contact between the two elements when in motion
B. Surface contact between the two elements when in motion
C. Elements of pairs not held together mechanically
D. Two elements that permit relative motion
Answer : A
8. In order to give a complete secondary balance of a multi-cylinder inline engine,
A. The algebraic sum of the secondary forces must be equal to zero
B. The algebraic sum of the couples about any point in the plane of the secondary forces must be equal to zero
C. Both (A) and (B)
D. None of these
Answer : C
A. The algebraic sum of the secondary forces must be equal to zero
B. The algebraic sum of the couples about any point in the plane of the secondary forces must be equal to zero
C. Both (A) and (B)
D. None of these
Answer : C
9. The frequency of oscillation at compared to earth will be
A. 6 times more
B. 6 times less
C. 2.44 times more
D. 2.44 times less
Answer : D
A. 6 times more
B. 6 times less
C. 2.44 times more
D. 2.44 times less
Answer : D
10. Ball and a Socket forms a
A. Turning pair
B. Rolling pair
C. Screw pair
D. Spherical pair
Answer : D
A. Turning pair
B. Rolling pair
C. Screw pair
D. Spherical pair
Answer : D
11. The maximum velocity of a particle moving with simple harmonic motion is
A. ?
B. ?r
C. ?²r
D. ?/r
Answer : B
A. ?
B. ?r
C. ?²r
D. ?/r
Answer : B
12. Effort of a governor is the
A. Mean force exerted at the sleeve for a given percentage change of speed
B. Workdone at the sleeve for maximum equilibrium speed
C. Mean force exerted at the sleeve for maximum equilibrium speed
D. None of the above
Answer : A
A. Mean force exerted at the sleeve for a given percentage change of speed
B. Workdone at the sleeve for maximum equilibrium speed
C. Mean force exerted at the sleeve for maximum equilibrium speed
D. None of the above
Answer : A
13. A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 Hz and 200 Hz respectively. The lowest critical speed is
A. 5,367 r.p.m.
B. 6,000 r.p.m.
C. 9,360 r.p.m.
D. 12,000 r.p.m.
Answer : A
A. 5,367 r.p.m.
B. 6,000 r.p.m.
C. 9,360 r.p.m.
D. 12,000 r.p.m.
Answer : A
14. Which of the following is an inversion of a double slider crank chain?
A. Oldham's coupling
B. Elliptical trammel
C. Scotch yoke mechanism
D. All of these
Answer : D
A. Oldham's coupling
B. Elliptical trammel
C. Scotch yoke mechanism
D. All of these
Answer : D
15. In a hydrodynamic journal bearing, there is
A. A very thin film of lubricant between the journal and the bearing such that there is contact between the journal and the bearing
B. A thick film of lubricant between the journal and the bearing
C. No lubricant between the journal and the bearing
D. A forced lubricant between the journal and the bearing
Answer : B
A. A very thin film of lubricant between the journal and the bearing such that there is contact between the journal and the bearing
B. A thick film of lubricant between the journal and the bearing
C. No lubricant between the journal and the bearing
D. A forced lubricant between the journal and the bearing
Answer : B
16. A spring controlled governor is found unstable. It can be made stable by
A. Increasing the spring stiffness
B. Decreasing the spring stiffness
C. Increasing the ball mass
D. Decreasing the ball mass
Answer : B
A. Increasing the spring stiffness
B. Decreasing the spring stiffness
C. Increasing the ball mass
D. Decreasing the ball mass
Answer : B
17. Rectangular bar in a rectangular hole is the following type of pair
A. Completely constrained motion
B. Partially constrained motion
C. Incompletely constrained motion
D. Freely constrained motion
Answer : A
A. Completely constrained motion
B. Partially constrained motion
C. Incompletely constrained motion
D. Freely constrained motion
Answer : A
18. If ?/?n = 2, where co is the frequency of excitation and ?n is the natural frequency of vibrations, then the transmissibility of vibration will the
A. 0.5
B. 1
C. 1.5
D. 2
Answer : B
A. 0.5
B. 1
C. 1.5
D. 2
Answer : B
19. In a multiple V-belt drive, if one of the belts is broken, then we should replace
A. The broken belt only
B. All the belts
C. The broken belt and the belts on either side of it
D. None of the above
Answer : B
A. The broken belt only
B. All the belts
C. The broken belt and the belts on either side of it
D. None of the above
Answer : B
20. The primary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is
A. 0° and 90°
B. 0° and 180°
C. 90° and 180°
D. 180° and 360°
Answer : B
A. 0° and 90°
B. 0° and 180°
C. 90° and 180°
D. 180° and 360°
Answer : B
21. In a gear having involute teeth, the normal to the involute is a tangent to the
A. Pitch circle
B. Base circle
C. Addendum circle
D. Dedendum circle
Answer : B
A. Pitch circle
B. Base circle
C. Addendum circle
D. Dedendum circle
Answer : B
22. In vibration isolation system, the transmissibility will be equal to unity, for all values of damping factor, if ?/?n is
A. Equal to 1
B. Equal to 2
C. Less than 2
D. Greater than 2
Answer : B
A. Equal to 1
B. Equal to 2
C. Less than 2
D. Greater than 2
Answer : B
23. Which of the following would constitute a link?
A. Piston, piston rod and cross head
B. Piston and piston rod
C. Piston rod and cross head
D. Piston, crank pin and crank shaft
Answer : A
A. Piston, piston rod and cross head
B. Piston and piston rod
C. Piston rod and cross head
D. Piston, crank pin and crank shaft
Answer : A
24. The two elements of a pair are said to form a _________ when they permit relative motion between them.
A. Open pair
B. Kinematic pair
C. Sliding pair
D. None of these
Answer : B
A. Open pair
B. Kinematic pair
C. Sliding pair
D. None of these
Answer : B
25. When one of the links of a kinematic chain is fixed, the chain is known as a
A. Structure
B. Mechanism
C. Inversion
D. Machine
Answer : B
A. Structure
B. Mechanism
C. Inversion
D. Machine
Answer : B
26. A universal joint is an example of
A. Higher pair
B. Lower pair
C. Rolling pair
D. Sliding pair
Answer : B
A. Higher pair
B. Lower pair
C. Rolling pair
D. Sliding pair
Answer : B
27. A higher pair has__________.
A. Point contact
B. Surface contact
C. No contact
D. None of the above
Answer : A
A. Point contact
B. Surface contact
C. No contact
D. None of the above
Answer : A
28. The axis of precession is __________ to the plane in which the axis of spin is going to rotate.
A. Parallel
B. Perpendicular
C. Both A and B
D. None of these
Answer : B
A. Parallel
B. Perpendicular
C. Both A and B
D. None of these
Answer : B
29. Which of the following has sliding motion?
A. Crank
B. Connecting rod
C. Crank pin
D. Crosshead
Answer : D
A. Crank
B. Connecting rod
C. Crank pin
D. Crosshead
Answer : D
30. The danger of breakage and vibration is maximum
A. Below the critical speed
B. Near the critical speed
C. Above the critical speed
D. None of these
Answer : B
A. Below the critical speed
B. Near the critical speed
C. Above the critical speed
D. None of these
Answer : B
31. The working depth of a gear is the radial distance from the
A. Pitch circle to the bottom of a tooth
B. Pitch circle to the top of a tooth
C. Top of a tooth to the bottom of a tooth
D. Addendum circle to the clearance circle
Answer : D
A. Pitch circle to the bottom of a tooth
B. Pitch circle to the top of a tooth
C. Top of a tooth to the bottom of a tooth
D. Addendum circle to the clearance circle
Answer : D
32. The velocity of the rubbing surface __________ with the distance from the axis of the bearing.
A. Increases
B. Decreases
C. Remain same
D. None of these
Answer : A
A. Increases
B. Decreases
C. Remain same
D. None of these
Answer : A
33. A rotor supported at A and B carries two masses as shown in the below figure. The rotor is 
A. Dynamically balanced
B. Statically balanced
C. Statically and dynamically balanced
D. Not balanced
Answer : C
A. Dynamically balanced
B. Statically balanced
C. Statically and dynamically balanced
D. Not balanced
Answer : C
34. The ratio of height of Porter governor (when length of arms and links are equal) to the height of Watt's governor is (where m = Mass of the ball, and M = Mass on the sleeve)
A. m/(m + M)
B. M/(m + M)
C. (m + M)/m
D. (m + M)/M
Answer : C
A. m/(m + M)
B. M/(m + M)
C. (m + M)/m
D. (m + M)/M
Answer : C
35. The maximum frictional force, which comes into play, when a body just begins to slide over the surface of the other body, is known as
A. Static friction
B. Dynamic friction
C. Limiting friction
D. Coefficient of friction
Answer : C
A. Static friction
B. Dynamic friction
C. Limiting friction
D. Coefficient of friction
Answer : C
36. In the below figure, PC is the connecting rod and OC is the crank making an angle ? with the line of stroke PO and rotates with uniform angular velocity at ? rad/s. The Klien's acceleration diagram for determining the acceleration of the piston P is shown by quadrilateral CQNO. The acceleration of the piston P with respect to the crankpin C is given by 
A. ?² × NO
B. ?² × CO
C. ?² × CN
D. ?² × QN
Answer : C
A. ?² × NO
B. ?² × CO
C. ?² × CN
D. ?² × QN
Answer : C
37. The motion between a pair which takes place in __________ is known as incompletely constrained motion.
A. One direction only
B. Two directions only
C. More than one direction
D. None of these
Answer : C
A. One direction only
B. Two directions only
C. More than one direction
D. None of these
Answer : C
38. Angle of ascent of cam is defined as the angle
A. During which the follower returns to its initial position
B. Of rotation of the cam for a definite displacement of the follower
C. Through which the cam rotates during the period in which the follower remains in highest position
D. Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
Answer : D
A. During which the follower returns to its initial position
B. Of rotation of the cam for a definite displacement of the follower
C. Through which the cam rotates during the period in which the follower remains in highest position
D. Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
Answer : D
39. The frictional torque transmitted by a cone clutch is same as that of
A. Flat pivot bearing
B. Flat collar bearing
C. Conical pivot bearing
D. Truncated conical pivot bearing
Answer : D
A. Flat pivot bearing
B. Flat collar bearing
C. Conical pivot bearing
D. Truncated conical pivot bearing
Answer : D
40. In steady state forced vibrations, the amplitude of vibrations at resonance is __________ damping coefficient.
A. Equal to
B. Directly proportional to
C. Inversely proportional to
D. Independent of
Answer : C
A. Equal to
B. Directly proportional to
C. Inversely proportional to
D. Independent of
Answer : C
41. Cam angle is defined as the angle
A. During which the follower returns to its initial position
B. Of rotation of the cam for a definite displacement of the follower
C. Through which, the cam rotates during the period in which the follower remains in the highest position
D. Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
Answer : B
A. During which the follower returns to its initial position
B. Of rotation of the cam for a definite displacement of the follower
C. Through which, the cam rotates during the period in which the follower remains in the highest position
D. Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
Answer : B
42. In Meyer's expansion valve, the main valve is driven by an eccentric having an angle of advance from
A. 10°-15°
B. 15°-25°
C. 25°-30°
D. 30°-40°
Answer : C
A. 10°-15°
B. 15°-25°
C. 25°-30°
D. 30°-40°
Answer : C
43. The radius of a friction circle for a shaft rotating inside a bearing is (where r = Radius of shaft, and tan ? = Coefficient of friction between the shaft and bearing)
A. r sin?
B. r cos?
C. r tan?
D. (r/2) cos?
Answer : A
A. r sin?
B. r cos?
C. r tan?
D. (r/2) cos?
Answer : A
44. The relation l = (2/3).(j + 2) apply only to kinematic chains in which lower pairs are used. This may be used to kinematic chains in which higher pairs are used, but each higher pair may be taken as equivalent to
A. One lower pair and two additional links
B. Two lower pairs and one additional link
C. Two lower pairs and two additional links
D. Any one of these
Answer : B
A. One lower pair and two additional links
B. Two lower pairs and one additional link
C. Two lower pairs and two additional links
D. Any one of these
Answer : B
45. A pantograph is a mechanism with
A. Lower pairs
B. Higher pairs
C. Rolling pairs
D. Turning pairs
Answer : A
A. Lower pairs
B. Higher pairs
C. Rolling pairs
D. Turning pairs
Answer : A
46. A rotary internal combustion engine has __________ cylinders.
A. Four
B. Five
C. Six
D. Seven
Answer : D
A. Four
B. Five
C. Six
D. Seven
Answer : D
47. Which is the false statement about the properties of instantaneous centre?
A. At the instantaneous center of rotation, one rigid link rotates instantaneously relative to another for the configuration of mechanism considered
B. The two rigid links have no linear velocities relative to each other at the instantaneous centre
C. The two rigid links which have no linear velocity relative to each other at this center have the same linear velocity to the third rigid link
D. The double centre can be denoted either by O2 or O12, but proper selection should be made
Answer : D
A. At the instantaneous center of rotation, one rigid link rotates instantaneously relative to another for the configuration of mechanism considered
B. The two rigid links have no linear velocities relative to each other at the instantaneous centre
C. The two rigid links which have no linear velocity relative to each other at this center have the same linear velocity to the third rigid link
D. The double centre can be denoted either by O2 or O12, but proper selection should be made
Answer : D
48. Transmission angle is the angle between
A. Input link and coupler
B. Input link and fixed link
C. Output link and coupler
D. Output link and fixed link
Answer : C
A. Input link and coupler
B. Input link and fixed link
C. Output link and coupler
D. Output link and fixed link
Answer : C
49. Cylindrical cams can be classified as
A. Circular
B. Tangent
C. Reciprocating
D. None of the above
Answer : D
A. Circular
B. Tangent
C. Reciprocating
D. None of the above
Answer : D
50. The Grubler's criterion for determining the degrees of freedom (n) of a mechanism having plane motion is (where l = Number of links, and j = Number of binary joints)
A. n = (l -1) - j
B. n = 2(l - 1) - 2j
C. n = 3(l - 1) - 2j
D. n = 4(l - 1) - 3j
Answer : C
A. n = (l -1) - j
B. n = 2(l - 1) - 2j
C. n = 3(l - 1) - 2j
D. n = 4(l - 1) - 3j
Answer : C
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