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

1. 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

2. 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

3. The factional torque for square thread at the mean radius r while raising load W is given by
A. T = W.r tan(? - ?)
B. T = W.r tan(? + ?)
C. T = W.r tan?
D. T = W.r tan?
Answer : B

4. Inertia force acts
A. Perpendicular to the acceleration force
B. Along the direction of acceleration force
C. Opposite to the direction of acceleration force
D. None of the above
Answer : C

5. 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

6. The ratio of maximum fluctuation of speed to the mean speed is called
A. Fluctuation of speed
B. Maximum fluctuation of speed
C. Coefficient of fluctuation of speed
D. None of these
Answer : C

7. The periodic time is given by (where ? = Angular velocity of the particle in rad/s)
A. ?/2?
B. 2?/?
C. ? × 2?
D. ?/?
Answer : B

8. A higher pair has__________.
A. Point contact
B. Surface contact
C. No contact
D. None of the above
Answer : A

9. The Hooke's joint consists of:
A. Two forks
B. One fork
C. Three forks
D. Four forks
Answer : A

10. Which of the following statement is correct for gears?
A. The addendum is less than the dedendum
B. The pitch circle diameter is the product of module and number of teeth
C. The contact ratio means the number of pairs of teeth in contact
D. All of the above
Answer : D

11. The velocity of sliding of meshing gear teeth is (Where ?? and ?? are angular velocities of meshing gears and y is distance between point of contact and the pitch point)
A. (?? + ??)y
B. (??/??)y
C. (?? × ??)y
D. (?? + ??)/y
Answer : C

12. When the primary direct crank of a reciprocating engine makes an angle of ? with the line of stroke, then the secondary direct crank will make an angle of _________ with the line of stroke.
A. ?/2
B. ?
C. 2?
D. 4?
Answer : C

13. The relative velocity of B with respect to A in a rigid link AB is
A. Parallel to AB
B. Perpendicular to AB
C. Along AB
D. At 45° to AB
Answer : B

14. For an isochronous Hartnell governor (where r? and r? = Maximum and minimum radius of rotation of balls respectively, S? and S? = Maximum and minimum force exerted on the sleeve respectively, and M = Mass on the sleeve)
A. (m.g + S?)/(m.g + S?) = r?/r?
B. (m.g - S?)/(m.g - S?) = r?/r?
C. S?/S? = r?/r?
D. S?/S? = r?/r?
Answer : A

15. Two pulleys of radii r? and r? and at distance x apart are connected by means of a cross belt drive. The length of the belt is
A. ? (r? + r?) + [(r? + r?)²/x] + 2x
B. ? (r? + r?) + [(r? - r?)²/x] + 2x
C. ? (r? - r?) + [(r? - r?)²/x] + 2x
D. ? (r? - r?) + [(r? + r?)²/x] + 2x
Answer : A

16. The magnitude of linear velocity of a point B on a link AB relative to point A is (Where ? = Angular velocity of the link AB)
A. ? × AB
B. ? × (AB)²
C. ?² × AB
D. (? × AB)²
Answer : A

17. The static balancing is satisfactory for low speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because, the
A. Unbalanced couples are caused only at higher speeds
B. Unbalanced forces are not dangerous at higher speeds
C. Effects of unbalances are proportional to the square of the speed
D. Effects of unbalances are directly proportional to the speed
Answer : C

18. The partial balancing means
A. Balancing partially revolving masses
B. Balancing partially reciprocating masses
C. Best balancing of engines
D. All of these
Answer : B

19. To transmit power from one rotating shaft to another whose axes are neither parallel nor intersecting, use?
A. Spur gear
B. Spiral gear
C. Bevel gear
D. Worm gear
Answer : D

20. The mechanism consisting of three turning pairs and one sliding pair, is called a
A. Single slider crank chain
B. Whitworth quick return motion mechanism
C. Crank and slotted lever quick return motion mechanism
D. All of the above
Answer : D

22. Elements of pairs held together mechanically is known as
A. Closed pair
B. Open pair
C. Mechanical pair
D. Rolling pair
Answer : A

23. When the axes of the first and last wheels are coaxial, then the train is known as
A. Simple train of wheels
B. Compound train of wheels
C. Reverted gear train
D. Epicyclic gear train
Answer : C

24. 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

25. 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

26. The condition for correct steering of a Davis steering gear is (where ? = Angle of inclination of the links to the vertical)
A. sin? = b/c
B. cos? = c/b
C. tan? = c/2b
D. cot? = c/2b
Answer : C

27. Sensitiveness of the governor is defined as the ratio of the
A. Mean speed to the maximum equilibrium speed
B. Mean speed to the minimum equilibrium speed
C. Difference of the maximum and minimum equilibrium speeds to the mean speed
D. Sum of the maximum and minimum equilibrium speeds to the mean speed
Answer : C

28. 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

29. When a rigid body is suspended vertically and it oscillates with a small amplitude under the action of the force of gravity, the body is known as
A. Simple pendulum
B. Compound pendulum
C. Torsional pendulum
D. Second's pendulum
Answer : B

30. The frictional torque transmitted in a flat collar bearing, considering uniform pressure, is (where r? and r? = External and internal radii of collar respectively)
A. (1/2). ? W (r? + r?)
B. (2/3). ? W (r? + r?)
C. (1/2). ? W [(r?³ - r?³)/(r?² - r?²)]
D. (2/3). ? W [(r?³ - r?³)/(r?² - r?²)]
Answer : D

31. A Porter governor is a
A. Pendulum type governor
B. Dead weight governor
C. Spring loaded governor
D. Inertia governor
Answer : B

32. When brakes are applied to all the four wheels of a moving car, the distance travelled by the car before it is brought to rest, will be
A. Maximum
B. Minimum
C. Zero
D. None of these
Answer : B

33. If the opposite links of a four bar linkage are equal, the links will always form a
A. Triangle
B. Rectangle
C. Parallelogram
D. Pentagon
Answer : C

34. If the number of links in a mechanism is equal to l, then the numbers of possible inversions are equal to
A. l - 2
B. l - 1
C. l
D. l + 1
Answer : C

35. The steering of a ship means
A. Movement of a complete ship up and down in vertical plane about transverse axis
B. Turning of a complete ship in a curve towards right or left, while it moves forward
C. Rolling of a complete ship sideways
D. None of the above
Answer : B

36. The relation between number of links (l) and number of joints (j) in a kinematic chain is
A. l = (1/2).(j + 2)
B. l = (2/3).(j + 2)
C. l = (3/4).(j + 3)
D. l = j + 4
Answer : B

37. An exact straight line motion mechanism is a
A. Scott-Russell's mechanism
B. Hart's mechanism
C. Peaucellier's mechanism
D. All of these
Answer : D

38. Angle of action of cam is defined as the angle
A. Of rotation of the cam for a definite displacement of the follower
B. Through which the cam rotates during the period in which the follower remains in the highest position
C. Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
D. Moved by the cam from beginning of ascent to the termination of descent
Answer : D

39. The amplitude of vibration is always __________ the radius of the circle.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : A

40. For dynamic balancing of a shaft
A. The net dynamic force acting on the shaft is equal to zero
B. The net couple due to the dynamic forces acting on the shaft is equal to zero
C. Both (A) and (B)
D. None of the above
Answer : C

41. 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

42. A watt's governor can work satisfactorily at speeds from
A. 60 to 80 r.p.m.
B. 80 to 100 r.p.m.
C. 100 to 200 r.p.m.
D. 200 to 300 r.p.m.
Answer : A

43. Which type of gear train is used in clock mechanism to join hour hand and minute hand?
A. Simple gear train
B. Compound gear train
C. Reverted gear train
D. Epicyclic gear train
Answer : D

44. The coriolis component of acceleration leads the sliding velocity by
A. 45°
B. 90°
C. 135°
D. 180°
Answer : B

45. 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

46. 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

47. The unbalanced primary forces in a reciprocating engine are
A. Balanced completely
B. Balanced partially
C. Balanced by secondary forces
D. Not balanced
Answer : B

48. The secondary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is
A. 0° and 90°
B. 180° and 360°
C. Both (A) and (B)
D. None of these
Answer : C

49. 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 minimum length of the coupler will be
A. 45 mm
B. Slightly less than 45 mm
C. Slightly more than 45 mm
D. 95 mm
Answer : C

50. The balancing weights are introduced in planes parallel to the plane of rotation of the disturbing mass. To obtain complete dynamic balance, the minimum number of balancing weights to be introduced in different planes is
A. 1
B. 2
C. 3
D. 4
Answer : B