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

1. 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

2. 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

3. 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

4. In a reciprocating steam engine, when the crank has turned from inner dead centre through an angle ?, the angular velocity of the connecting rod is given by
A. ? sin?/(n² - sin²?)^1/2
B. ? cos?/(n² - cos²?)^1/2
C. ? sin?/(n² - cos²?)^1/2
D. ? cos?/(n² - sin²?)^1/2
Answer : D

5. In a vibrating system, if the actual damping coefficient is 40 N/m/s and critical damping coefficient is 420 N/m/s, then logarithmic decrement is equal to
A. 0.2
B. 0.4
C. 0.6
D. 0.8
Answer : C

6. The equation of motion for a vibrating system with viscous damping is (d²x/dt²) + (c/m).(dx/dt) + (s/m).x = 0, if the roots of the equation are __________ then the system will be under damped.
A. Equal
B. Real
C. Complex conjugate
D. None of these
Answer : C

7. The primary unbalanced force is maximum _________ in one revolution of the crank.
A. Twice
B. Four times
C. Eight times
D. Sixteen times
Answer : A

8. 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

9. The direction of linear velocity of any point on a link with respect to another point on the same link is
A. Parallel to the link joining the points
B. Perpendicular to the link joining the points
C. At 45° to the link joining the points
D. None of the above
Answer : B

10. The swaying couple is maximum or minimum when the angle of inclination of the crank to the line of stroke (?) is equal to
A. 90° and 180°
B. 45° and 225°
C. 180° and 270°
D. 270° and 360°
Answer : B

11. When the two elements of a pair have __________ when in motion, it is said to a lower pair.
A. Line or point contact
B. Surface contact
C. Body contact
D. None of these
Answer : B

12. When the nature of contact between the elements of a pair is such that one element can turn about the other by screw threads, the pair is known as a
A. Screw pair
B. Spherical pair
C. Turning pair
D. Sliding pair
Answer : A

13. 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

14. The face of the tooth is the
A. Surface of the top of tooth
B. Surface of tooth above the pitch surface
C. Width of tooth below the pitch surface
D. Width of tooth measured along the pitch circle
Answer : B

15. 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

16. 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

17. 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

18. Which of the following statement is correct for involute gears?
A. The interference is inherently absent.
B. The variation in centre distance of shafts increases radial force.
C. A convex flank is always in contact with concave flank.
D. The pressure angle is constant throughout the teeth engagement.
Answer : D

19. 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

20. TJIE horse power transmitted by a belt is dependent upon
A. Tension on tight side of belt
B. Tension on slack side of belt
C. Radius of pulley
D. All of the above
Answer : D

21. The lower pair is a
A. Open pair
B. Closed pair
C. Sliding pair
D. Point contact pair
Answer : B

22. The Bifilar suspension method is used to determine
A. Natural frequency of vibration
B. Position of balancing weights
C. Moment of inertia
D. Centripetal acceleration
Answer : C

23. The frictional torque transmitted in a truncated conical pivot bearing, considering uniform pressure, is
A. (1/2). ? W cosec? (r? + r?)
B. (2/3). ? W cosec? (r? + r?)
C. (1/2). ? W cosec? [(r?³ - r?³)/(r?² - r?²)]
D. (2/3). ? W cosec? [(r?³ - r?³)/(r?² - r?²)]
Answer : D

24. Coriolis component acts
A. Perpendicular to sliding surfaces
B. Along sliding surfaces
C. Somewhere in between above two
D. None of the above
Answer : A

25. The example of completely constrained motion is a
A. Motion of a piston in the cylinder of a steam engine
B. Motion of a square bar in a square hole
C. Motion of a shaft with collars at each end in a circular hole
D. All of the above
Answer : D

26. 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

27. In a simple train of wheels, the velocity ratio __________ the intermediate wheels.
A. Depends upon
B. Is independent of
C. Either A or B
D. None of these
Answer : B

28. The Kutzbach criterion for determining the number of degrees of freedom (n) is (where l = number of links, j = number of joints and h = number of higher pairs)
A. n = 3(l - 1) - 2j - h
B. n = 2(l - 1) -2j - h
C. n = 3(l - 1) - 3j - h
D. n = 2(l - 1) - 3j - h
Answer : A

29. Efficiency of a screw jack is given by
A. tan (? + ?)/tan?
B. tan?/tan (? +?)
C. tan (? - ?)/tan?
D. tan?/tan (? - ?)
Answer : B

30. The minimum force required to slide a body of weight W on a rough horizontal plane is
A. W sin?
B. W cos?
C. W tan?
D. W cosec?
Answer : A

31. When the sleeve of a Porter governor moves upwards, the governor speed
A. Increases
B. Decreases
C. Remain unaffected
D. First increases and then decreases
Answer : A

32. In its simplest form, a cam mechanism consists of following number of links
A. 1
B. 2
C. 3
D. 4
Answer : C

33. 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

34. The centrifugal tension in belts
A. Increases power transmitted
B. Decreases power transmitted
C. Have no effect on power transmitted
D. Increases power transmitted upto a certain speed and then decreases
Answer : C

35. The centre of gravity of a coupler link in a four bar mechanism will experience
A. No acceleration
B. Only linear acceleration
C. Only angular acceleration
D. Both linear and angular acceleration
Answer : D

36. A completely constrained motion can be transmitted with.
A. 1 link with pin joints
B. 2 links with pin joints
C. 3 links with pin joints
D. 4 links with pin joints
Answer : D

37. A mechanism consisting of four links is called a __________ mechanism.
A. Simple
B. Compound
C. Binary
D. None of these
Answer : A

38. The frictional torque transmitted in a flat collar bearing, considering uniform wear, 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 : A

39. 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

40. A disc is a spinning with an angular velocity ? rad/s about the axis of spin. The couple applied to the disc causing precession will be (where I = Mass moment of inertia of the disc, and ?P = Angular velocity of precession of the axis of spin)
A. (1/2).I?²
B. I?²
C. (1/2). I ? ?_P
D. I ? ?_P
Answer : D

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