IBPS SO - Theory of Machines 1000+ MCQ [Solved] PDF Download

1. The Klein's diagram is used when
A. Crank has uniform angular velocity
B. Crank has nonuniform angular velocity
C. Crank has uniform angular acceleration
D. Crank has nonuniform angular acceleration
Answer : A

2. Which of the following mechanism is an approximate straight line motion mechanism?
A. Watt's mechanism
B. Grasshopper mechanism
C. Robert's mechanism
D. All of these
Answer : D

3. Which of the following is used to control the speed variations of the engine caused by the fluctuations of the engine turning moment?
A. D-slide valve
B. Governor
C. Flywheel
D. Meyer's expansion valve
Answer : C

4. The partial balancing of reciprocating parts in locomotives produces
A. Hammer blow
B. Swaying couple
C. Variation in tractive force along the line of stroke
D. All of the above
Answer : D

5. The maximum value of the pressure angle in case of cam is kept as
A. 10°
B. 14°
C. 20°
D. 30°
Answer : D

6. 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, if N coincides with O, then
A. Acceleration and velocity of the piston P is zero
B. Acceleration and velocity of the piston P is maximum
C. Acceleration of the piston P is zero and its velocity is maximum
D. Acceleration of the piston P is maximum and its velocity is zero
Answer : C

7. 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

8. The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be
A. To dip the nose and tail
B. To raise the nose and tail
C. To raise the nose and dip the tail
D. To dip the nose and raise the tail
Answer : C

9. In an ideal machine, the output as compared to input is
A. Less
B. More
C. Equal
D. May be less or more depending on efficiency
Answer : C

10. At the nodal point in a shaft, the amplitude for torsional vibration will be
A. Minimum
B. Maximum
C. Zero
D. Infinity
Answer : C

11. A body in motion will be subjected to coriolis acceleration when that body is
A. In plane rotation with variable velocity
B. In plane translation with variable velocity
C. In plane motion which is a resultant of plane translation and rotation
D. Restrained to rotate while sliding over another body
Answer : D

12. 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

13. Which of the following is an example of a higher pair?
A. Toothed gearing
B. Belt and rope drive
C. Ball and roller bearing
D. All of these
Answer : D

14. 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

15. The Ackermann steering mechanism is preferred to the Davis type in automobiles because
A. The former is mathematically accurate
B. The former is having turning pair
C. The former is most economical
D. The former is most rigid
Answer : B

16. A mass of 1 kg is attached to the end of a spring with a stiffness of 0.7 N/mm. The critical damping coefficient of this system is
A. 1.4 N-s/m
B. 18.52 N-s/m
C. 52.92 N-s/m
D. 529.2 N-s/m
Answer : C

17. The unbalanced force due to revolving masses
A. Varies in magnitude but constant in direction
B. Varies in direction but constant in magnitude
C. Varies in magnitude and direction both
D. Constant in magnitude and direction both
Answer : B

18. Which of the following is false statement in respect of differences between machine and structure?
A. Machines transmit mechanical work, whereas structures transmit forces
B. In machines, relative motion exists between its members, whereas same does not exist in case of structures
C. Machines modify movement and work, whereas structures modify forces
D. Efficiency of machines as well as structures is below 100%
Answer : D

19. The velocity of piston in a reciprocating steam engine is given by (where ? = Angular velocity of crank, r = Radius of crank pin circle, ? = Angle turned by crank from inner dead centre, and n = Ratio of length of connecting rod to the radius of crank)
A. ?r [sin ? + (sin 2?/n)]
B. ?r [cos ? + (cos 2?/n)]
C. ?²r [sin ? + (sin 2?/n)]
D. ?²r [cos ? + (cos 2?/n)]
Answer : A

20. The critical speed of a shaft in revolution per second is __________ as that of natural frequency of transverse vibration.
A. Same
B. Different
C. Unpredictable
D. None of these
Answer : A

21. 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

22. The ratio of the number of teeth to the pitch circle diameter in millimetres, is called
A. Circular pitch
B. Diametral pitch
C. Module
D. None of these
Answer : B

23. The periodic time of a compound pendulum is __________ when the distance between the point of suspension and the centre of gravity is equal to the radius of gyration of the body about its centre of gravity.
A. Zero
B. Minimum
C. Maximum
D. None of these
Answer : B

24. 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

25. A pantograph is a mechanism with
A. Lower pairs
B. Higher pairs
C. Rolling pairs
D. Turning pairs
Answer : A

26. In considering friction of a V-thread, the virtual coefficient of friction (??) is given by
A. ?? = ? sin?
B. ?? = ? cos?
C. ?? = ?/sin?
D. ?? = ?/cos?
Answer : D

27. The natural frequency of free transverse vibrations due to uniformly distributed load acting over a simply supported shaft is (where ?S = Static deflection of simply supported shaft due to uniformly distributed load)
A. 0.4985/ ??S
B. 0.5615/ ??S
C. 0.571/ ??S
D. 0.6253/ ??S
Answer : B

28. A motor car moving at a certain speed takes a left turn in a curved path. If the engine rotates in the same direction as that of wheels, men due to centrifugal forc
A. The reaction on me inner wheels increases and on the outer wheels decreases
B. The reaction on the outer wheels increases and on the inner wheels decreases
C. The reaction on the front wheels increases and on the rear wheels decreases
D. The reaction on the rear wheels increases and on the front wheels decreases
Answer : B

29. A shaft has an attached disc at the centre of its length. The disc has its centre of gravity located at a distance of 2 mm from the axis of the shaft. When the shaft is allowed to vibrate in its natural bow-shaped mode, it has a frequency of vibration of 10 rad/s. When the shaft is rotated at 300 r.p.m., it will whirl with a radius of
A. 2 mm
B. 2.22 mm
C. 2.50 mm
D. 3.0 mm
Answer : B

30. 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

31. The coriolis component of acceleration is taken into account for
A. Slider crank mechanism
B. Four bar chain mechanism
C. Quick return motion mechanism
D. All of these
Answer : C

32. When a point moves along a straight line, its acceleration will have
A. Radial component only
B. Tangential component only
C. Coriolis component only
D. Radial and tangential components both
Answer : B

33. In order to balance the reciprocating masses,
A. Primary forces and couples must be balanced
B. Secondary forces and couples must be balanced
C. Both (A) and (B)
D. None of these
Answer : C

34. When a ship travels in a sea, which of the effect is more dangerous
A. Steering
B. Pitching
C. Rolling
D. All of the above
Answer : B

35. The train value of a gear train is
A. Equal to velocity ratio of a gear train
B. Reciprocal of velocity ratio of a gear train
C. Always greater than unity
D. Always less than unity
Answer : B

36. The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in
A. Transverse vibrations
B. Torsional vibrations
C. Longitudinal vibrations
D. All of these
Answer : A

37. Which of the following is a higher pair?
A. Turning pair
B. Screw pair
C. Belt and pulley
D. None of the above
Answer : C

38. In a four-bar chain it is required to give an oscillatory motion to the follower for a continuous rotation of the crank. For the lengths of 50 mm of crank and 70 mm of the follower, determine theoretical maximum length of coupler. The distance between fixed pivots of crank and followers is
A. 95 mm
B. Slightly less than 95 mm
C. Slightly more than 95 mm
D. 45 mm
Answer : B

39. The Klein's diagram is useful to find
A. Displacement of various parts
B. Velocity of various parts
C. Acceleration of various parts
D. Angular acceleration of various parts
Answer : C

40. The two elements of a pair are said to form a higher pair, when they
A. Have a surface contact when in motion
B. Have a line or point contact when in motion
C. Are kept in contact by the action of external forces, when in motion
D. Permit relative motion
Answer : B

41. 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

42. For a kinematic chain to be considered as mechanism
A. Two links should be fixed
B. One link should be fixed
C. None of the links should be fixed
D. There is no such criterion
Answer : B

43. The power from the engine to the rear axle of an automobile is transmitted by means of
A. Worm and worm wheel
B. Spur gears
C. Bevel gears
D. Hooke's joint
Answer : D

44. Kinematic 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 : D

45. The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ? = Angular speed of crank, r = Radius of crank, and ? = Angle of inclination of crank to the line of stroke)
A. m.?².r cos?
B. c.m.?².r sin?
C. (1 - c).m.?².r (cos? - sin?)
D. m.?².r (cos? - sin?)
Answer : C

46. The radial distance of a tooth from the pitch circle to the bottom of the tooth is called
A. Dedendum
B. Addendum
C. Clearance
D. Working depth
Answer : A

47. The coriolis component of acceleration exists whenever a point moves along a path that has
A. Linear displacement
B. Rotational motion
C. Gravitational acceleration
D. Tangential acceleration
Answer : B

48. Which of the following has sliding motion?
A. Crank
B. Connecting rod
C. Crank pin
D. Crosshead
Answer : D

49. In under damped vibrating system, if x? and x? are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to
A. x?/x?
B. log(x?/x?)
C. log_e(x?/x?)
D. log(x?.x?)
Answer : B

50. The acceleration of the reciprocating roller follower when it has contact with the straight flanks of the tangent cam, is given by
A. ?². (r? r?). (1 - cos² ?)
B. ?². (r? + r?). (1 + cos² ?)
C. ?². (r? + r?). [(2 - cos² ?)/cos³ ?]
D. ?². (r? - r?). (1 - sin² ?)
Answer : C