1000+ Theory of Machines Multiple Choice Question Answer [Solved]

1. In gramophones for adjusting the speed of the turntable, the following type of governor is commonly employed
A. Hartung governor
B. Wilson Hartnell governor
C. Pickering governor
D. Inertia governor
Answer : C

2. Cam size depends upon
A. Base circle
B. Pitch circle
C. Prime circle
D. Outer circle
Answer : A

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

4. 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

5. In a four bar chain or quadric cycle chain
A. Each of the four pairs is a turning pair
B. One is a turning pair and three are sliding pairs
C. Two are turning pairs and two are sliding pairs
D. Three are turning pairs and one is a sliding pair
Answer : A

6. Which of the following statement is correct as regard to the difference between a machine and a structure?
A. The parts of a machine move relative to one another, whereas the members of a structure do not move relative to one another
B. The links of a machine may transmit both power and motion, whereas the members of a structure transmit forces only
C. A machine transforms the available energy into some useful work, whereas in a structure no energy is transformed into useful work
D. All of the above
Answer : D

7. Which of the following governor is used to drive a gramophone?
A. Watt governor
B. Porter governor
C. Pickering governor
D. Hartnell governor
Answer : C

8. A slider crank chain consists of following numbers of turning and sliding pairs
A. 1, 3
B. 2, 2
C. 3, 1
D. 4, 0
Answer : C

9. Module of a gear is
A. D/T
B. T/D
C. 2D/T
D. 2T/D
Answer : A

10. A rotary internal combustion engine has __________ cylinders.
A. Four
B. Five
C. Six
D. Seven
Answer : D

11. 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

12. 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

13. The effort of a Porter governor is equal to (where c = Percentage increase in speed, m = Mass of ball, and M = Mass on the sleeve)
A. c (m - M) g
B. c (m + M) g
C. c/(m + M) g
D. c/(m - M) g
Answer : B

14. 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

15. An imaginary circle which by pure rolling action, gives the same motion as the actual gear, is called
A. Addendum circle
B. Dedendum circle
C. Pitch circle
D. Clearance circle
Answer : C

16. The Coriolis component of acceleration acts
A. Along the sliding surface
B. Perpendicular to the sliding surface
C. At 45° to the sliding surface
D. Parallel to the sliding surface
Answer : B

17. A point on a connecting link (excluding end points) of a double slider crank mechanism traces a
A. Straight line path
B. Hyperbolic path
C. Parabolic path
D. Elliptical path
Answer : D

18. 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

19. The ratio of the driving tensions for V-belts is __________ times that of flat belts. (Where ? = Semi-angle of the groove)
A. sin?
B. cos?
C. cosec?
D. sec?
Answer : C

20. Consider the following mechanisms:
1. Oscillating cylinder engine mechanism
2. Toggle mechanism
3. Radial cylinder engine mechanism
4. Quick return mechanism Which of the above are inversions of slider crank mechanism?
A. 1, 2 and 4
B. 2, 3 and 4
C. 1, 2 and 3
D. 1, 3 and 4
Answer : D

21. A cam with a roller follower would constitute following type of pair
A. Lower pair
B. Higher pair
C. Open pair
D. Close pair
Answer : B

22. Hammer blow
A. Is the maximum horizontal unbalanced force caused by the mass provided to balance the reciprocating masses.
B. Is the maximum vertical unbalanced force caused by the mass added to balance the reciprocating masses
C. Varies as the square root of the speed
D. Varies inversely with the square of the speed
Answer : B

23. The included angle for the V-belt is usually
A. 10° to 20°
B. 20° to 30°
C. 30° to 40°
D. 60° to 80°
Answer : C

24. In a pantograph, all the pairs are
A. Turning pairs
B. Sliding pairs
C. Spherical pairs
D. Self-closed pairs
Answer : A

25. 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

26. Typewriter constitutes
A. Machine
B. Structure
C. Mechanism
D. Inversion
Answer : C

27. The frictional torque transmitted in a flat pivot bearing, considering uniform pressure, is (where ? = Coefficient of friction, W = Load over the bearing, and R = Radius of bearing surface)
A. (1/2) ? W R
B. (2/3) ? W R
C. (3/4) ? W R
D. ? W R
Answer : B

28. In a mechanism, the fixed instantaneous centres are those centres which
A. Remain in the same place for all configurations of the mechanism
B. Vary with the configuration of the mechanism
C. Moves as the mechanism moves, but joints are of permanent nature
D. None of the above
Answer : A

29. Which gear train is used for higher velocity ratios in a small space?
A. Simple gear train
B. Compound gear train
C. Reverted gear train
D. Epicyclic gear train
Answer : D

30. When two pulleys are connected by means of a cross belt drive, then both the pulleys will rotate in __________ directions.
A. Same
B. Opposite
C. Perpendicular
D. None of these
Answer : B

31. The frictional torque transmitted in a flat pivot bearing with assumption of uniform pressure is _________ as compared to uniform wear.
A. Less
B. More
C. Same
D. None of these
Answer : B

32. If the radius of gyration of a compound pendulum about an axis through e.g. is more, then its frequency of oscillation will be
A. Less
B. More
C. Same
D. Data are insufficient to determine same
Answer : A

33. In order to facilitate starting of locomotive in any position, the cranks of a locomotive with two cylinders, are placed at
A. 45° to each other
B. 90° to each other
C. 120° to each other
D. 180° to each other
Answer : B

34. The rotor of a ship rotates in clockwise direction when viewed from stern and the ship takes a left turn. The effect of gyroscopic couple acting on it will be
A. To raise the bow and stern
B. To lower the bow and stern
C. To raise the bow and lower the stern
D. To raise the stern and lower the bow
Answer : C

35. When a mass of a critically damped single degree of freedom system is deflected from its equilibrium position and released, then it will
A. Return to equilibrium position without oscillation
B. Oscillate with increasing time period
C. Oscillate with decreasing amplitude
D. Oscillate with constant amplitude
Answer : B

36. For low and moderate speed engines, the cam follower should move with
A. Uniform velocity
B. Simple harmonic motion
C. Uniform acceleration and retardation
D. Cycloidal motion
Answer : B

37. 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

38. In S.H.M., the velocity vector w.r.t. displacement vector
A. Leads by 90°
B. Lags by 90°
C. Leads by 180°
D. Are in phase
Answer : A

39. A kinematic chain is known as a mechanism when
A. None of the links is fixed
B. One of the links is fixed
C. Two of the links are fixed
D. None of these
Answer : B

40. In order to double the period of a simple pendulum, the length of the string should be
A. Halved
B. Doubled
C. Quadrupled
D. None of these
Answer : C

41. The instantaneous centre of a rigid thin disc rolling on a plane rigid surface is located at
A. The centre of the disc
B. The point of contact
C. An infinite distance on the plane surface
D. The point on the circumference situated vertically opposite to the contact point
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

43. Under logarithmic decrement, the amplitude of successive vibrations are
A. Constant
B. In arithmetic progression
C. In geometric progression
D. In logarithmic progression
Answer : C

44. Klein's construction is useful to determine
A. Velocity of various parts
B. Acceleration of various parts
C. Displacement of various parts
D. Angular acceleration of various parts
Answer : B

45. Relationship between the number of links (L) and number of pairs (P) is
A. P = 2L - 4
B. P = 2L + 4
C. P = 2L + 2
D. P = 2L - 2
Answer : C

46. There are six gears A, B, C, D, E and F in a compound train. The numbers of teeth in the gears are 20, 60, 30, 80, 25 and 75 respectively. The ratio of angular speeds of the driven (F) to the driver (A) of the drive is
A. 1/24
B. 1/8
C. 4/15
D. 12
Answer : A

47. Creep in belt drive is due to
A. Material of the pulley
B. Material of the belt
C. Larger size of the driver pulley
D. Uneven extensions and contractions due to varying tension
Answer : D

48. 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

49. 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

50. The tractive force is maximum or minimum when the angle of inclination of crank with the line of stroke (?) is equal to
A. 0° and 90°
B. 90° and 180°
C. 135° and 315°
D. 270° and 360°
Answer : B